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COURSE BOOK IN GENERAL BIOLOGY Chapter 1 BIOLOGY: THE SCIENCE OF LIFE [1] COURSE BOOK IN GENERAL BIOLOGY [2] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. Science and the Scientific Method Objectives: 1. to explain the concept and nature of science 2. to discuss the scientific method The Nature of Science Science comes from a Latin word scie, meaning, to know. Itis asystematized body of knowledge or information that aims to provide reliable information on different phenomena through experiment and observations. Science is an objective, logical, and repeatable attempt to understand the principles and forces operating in the natural universe. Good science is not dogmatic, but should be viewed as an ongoing process of testing and evaluation. The very nature of science requiring its conclusions to be based on evidences limits its range of applications.Questions that do not lead to testable hypothesis are outside the domain of science, thus science cannot answer all categories of questions. The Scientific Method The scientific method is a process or sequence of activities undertaken to gather information and to come to conclusions about the natural world. When one deliberately engages in the scientific method, he could be motivated by mere curiosity or by just the need to know about the [3] COURSE BOOK IN GENERAL BIOLOGY event or by the subject of his interest. He could also be driven by his desire to produce material that will be a source of economic gains. Observation New observations are made, and previous data are studied Hypothesis Input from various sources is used to formulate testable statement Conclusion Experiment/Observation s The hypothesis is tested by experiment or further observations The results are analyzed and the hypothesis is supported or rejected Scientific Theory Many experiments and observations support a theory Fig 1. The Flow Diagram of the Scientific Process. (Source: Mader, S.S. 2004. Biology.8th edition. McGraw Hill, USA.) [4] COURSE BOOK IN GENERAL BIOLOGY Making Observations and Gathering Knowledge About A Phenomenon (Initial Observation, Recognition of a Problem and Defining It, Further Observation and Expanding Knowledge) Man has the inherent capacity to observe the things around him. Careful observation could make one recognize that there is a problem or a phenomenon that is worthy of further attention and study. Afterinitial observations, details not previously observed can be determined using instrumentation.Search and review of related literature (books, scientific journals, online sources, etc.) should also be undertaken to learn more about the problem. Formulation of Hypothesis (Use of inductive reasoning to provide a tentative solution to the problem) Scientists use generalizations to come up with a hypothesis, which is an intelligent guess that is a possible explanation for a natural event. The hypothesis is presented as an actual statement and must be testable. Testing of Hypothesis (Experimentation and Conduct of Further Observations) In this phase, the scientist uses deductive reasoning involving the “if, then” logic. Foresight or the capability to predict what will happen next is necessary to guide the scientist on how to go about his experiment. The scientist must come up with an experimental design that will make him generate meaningful results. Usually a “control” or “control group” is set up side by side with the experimental group. This contains all components and undergoes all parts of the experiment except for the factor being tested. [5] COURSE BOOK IN GENERAL BIOLOGY Models (representation of the actual object) can be used in experimentation. They could be done through computer simulations or use of laboratory animals. If the experiment or observation produces a discrepancy between the prediction and the observable fact, then the scientist must change his hypothesis or redo the experiment to verify further until he is fully convinced of findings (validation process). Drawing of Conclusion (Analysis of Data to Determine whether the Hypothesis is Supported or Not, Publication of Results) Data are results of the experiment which may lead one to accept or reject the hypothesis initially formulated. These should be observable and objective. Mathematical data are usually presented in tabulated and graphical forms and may require statistical analysis to confirm validity or significance. A conclusion is the answer to the problem and based on a supported hypothesis. Science is a progressive process such that the conclusion of one experiment can lead to the hypothesis for another experiment. The results that do not support the hypothesis may be used by scientists to formulate another hypothesis to be tested. Conclusions from many different but related experiments may lead to the development of a Scientific Theory, a general concept about the natural world. A theory, therefore, is a hypothesis that has been repeatedly and extensively tested and always found to be true. However, no theory in science is ever absolutely and finally proven. Scientists should be ready to alter or even abandon their most cherished generalizations when new facts contradict them (Keeton and McFadden, 1983). [6] COURSE BOOK IN GENERAL BIOLOGY Name: _______________________________ Score ___________ Course & Year: _______________________ Date ___________ Exercise No. 1 Matching Type. Match Column A to Column B. Write the letter of your answer on the column provided for this. Answer Column A Column B 1. Scientific Method A. an intelligent guess that serves as a tentative answer to a problem or explanation of a natural event 2. Hypothesis B. a sequence of activities undertaken to gather information to explain events and facts in the natural world 3. Conclusion C. a set-up that allows one to prove or disprove the hypothesis 4. Theory D. the final answer to the problem based on a supported hypothesis 5. Experimentation E. a hypothesis that has been repeatedly and extensively tested and always found to be true. F. a search of related literature to know more about the problem [7] COURSE BOOK IN GENERAL BIOLOGY 2. Think of a problem which could be solved applying the scientific method. State clearly your hypothesis. Show/illustrate the experimental set up that you intend to put up to test your hypothesis. [8] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Biology as a Science Objectives: 1. to define biology and discuss its relevance to everyday life 2. to explain the fields of study in biology The word Biology comes from Greek words “bios”and “logos”which means the study of life. It involves the study of various organisms ranging from one-celled bacteria to the more complex multi-cellular plants and animals. Its concerns include structures, functions, growth, origin, reproduction, distribution and classification of living things, among others . Biology is the most diverse of all sciences. Through biology, one becomes familiar with how the body works, learns how diseases are spread and how they are fought through natural defenses and by medications, learns the intricacies of development from single cell to whole human being, and understands how plants capture the solar energy that ultimately sustains nearly all life. There are two main divisions of Biology: Zoology and Botany, the study of animals and plants, respectively, these branched out to include Microbiology, the study of microscopic organisms. The study of life is subdivided further into various fields of specialization. These include the following: Anatomy is the study of internal structures of living things [9] COURSE BOOK IN GENERAL BIOLOGY Morphology is the study of gross structures of living things Physiology is the study of functions or processes in living things Molecular Biology is the study of the chemical components of cells and their interactions Ecology is the study of relationships of living things with each otherand their interaction with the environment Taxonomy involves identification and classification of living things Genetics refers to the study of heredity and variation Embryology is the study of the formation and early development of organisms Cytology is the study of structure and function of cells Evolution is the study of the origin and diversity of organisms Paleontology is the study of fossils and their distribution in time Biogeography is the study of the distribution of plants and animals on earth Biology can also be subdivided according to the specific kind of organism namely: Ornithology, the study of birds; ornis means birds Entomology, the study of insects; entomon means insects Ichthyology , the study of fishes; ichthys means fishes Helmintology, the study of worms; helmis means worms Mammalogy, the study of mammals; mamma means breast Conchology, the study of shells; concha means mussels [10] COURSE BOOK IN GENERAL BIOLOGY Anthropology, the study of man; anthropo meansman Parasitology, the study of organisms that live and subsist on (ectoparasite) or in (endoparasite) other living organisms [11] COURSE BOOK IN GENERAL BIOLOGY [12] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________________ Score ___________ Course & Year: __________________________ Date ___________ Exercise No. 2 I. Identification: Give the field of biology concerned where the following organisms are studied. Place your answer on the space provided for. 1. earthworm __________________________ 2. stinkbugs __________________________ 3. native chicken __________________________ 4. milkfish __________________________ 5. kangaroos __________________________ 6. clams, pond snail __________________________ 7. tape worm __________________________ 8. blue whale __________________________ 9. lady bugs __________________________ 10. flukes __________________________ [13] COURSE BOOK IN GENERAL BIOLOGY II.Matching Type: Match the different branches of biology (column A) to their respective definition, description or concern (column B). Write the letter of your choice on the space provided for. Ans Column A 1. Physiology Column B A. distribution of plants and animals on earth 2. Ecology B. formation and early development of organisms 3. Cytology C. identification and classification of living things 4. Molecular D. relationship between organisms and Biology their environment 5. Genetics E. heredity and variation 6. Cytology F. functions and processes in living things 7. Taxonomy G. structure and functions at cellular level 8. Biogeography H. gross structures of living things 9. Morphology I. internal structures of living things 10. Anatomy J. chemical components, interactions and functions K. origin and differentiation of organisms L. fossil studies [14] COURSE BOOK IN GENERAL BIOLOGY III. Essay: Why do we study biology? Give at least three reasons why it is necessary to study living things. ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ __________________________________________ [15] COURSE BOOK IN GENERAL BIOLOGY [16] COURSE BOOK IN GENERAL BIOLOGY Lesson 3. Attributes of Life Objectives: 1. to explain the characteristics of living things 2.to distinguish living things from non-living things Living things on earth are composed of chemicals and are governed by the same laws of physics and chemistry that govern nonliving objects. Although living things are diverse, they share characteristics that distinguish them from non-living things, such as the following: 1. Living things are composed of cells. All living things are made up of cells. Some organisms have only one cell, some just have a few while others are made up of billions of cells. The living part of the cell known as the protoplasm, is made up of substances that are in constant state of chemical activity that establishes the “living condition”. The composition of the protoplasm varies from one species to another, between individuals of the same species, in different parts of the individual and in the same part at different times. 2. Living things have definite organization. All living things exhibit complex but ordered definite organization. This is manifested in the organization of chemicals at the molecular level which comprise the cell, the smallest basic unit of life. Cells are organized to form tissues, tissues combine to form organs, organs work together to form systems and organs systems together compose an organism. The organization extends beyond the individual organism. [17] Individuals of the same COURSE BOOK IN GENERAL BIOLOGY species form the population, which interact with other populations forming communities within the ecosystem. Finally, the earth’s ecosystems comprise the biosphere. 3. Living things require energy from the environment and produce waste energy and chemicals. Living things need continuous supply of energy in order to stay alive. The sun is the ultimate source of energy for all living things.Both plants and animals, however, obtain energy more directly by the breakdown of complex chemical substances we call food. This chemical process for getting energy and using it for the maintenance of life called metabolism, has two opposing activities; anabolism and catabolism. The constant expenditure of energy (catabolism) demands a corresponding intake of energy by the cell for restorative purposes (anabolism). These occur continuously and are intricately interdependent so that it is difficult to distinguish one from the other. During metabolism, waste energy in the form of heat and chemical waste like CO2 are eliminated or released. 4. Living things grow and develop. Growth pertains to enlargement or increase in size. Nonliving things such as stones and mountains also increase their sizes but this is due to the addition of more materials on their surfaces (accretion). Living things grow by assimilation – a process wherein large and complicated molecules are formed and incorporated in the organism. [18] COURSE BOOK IN GENERAL BIOLOGY Growth may be uniform in some parts of the body or it may be differential, such that growth may be greater in some parts than in other parts of the body. Growth may occur throughout the life span of an organism, or only for some parts of its life history. Usually, when maturity is reached, growth is reduced to repair of worn-out parts and/or to the replacement of vital /important substances. Development is the series of orderly changes that occur in an offspring from its beginning to its maturity. It includes the following stages: a. beginning; b. growth; c. maturity; d. decline and e. death. 5. Living things reproduce and inherit characteristics from parents. Reproduction is the process by which organisms produce offspring that are similar to themselves. It takes three forms: 1. division of a cell, as in simple, one-celled organisms. 2. formation of reproductive cells (gametes) such as the egg cell and sperm cells which unites in fertilization to form the zygote. 3. removal from a parent organism a part capable of independent growth. Inheritance is the passing of characteristics from one generation to the next. Living things inherit from their parents a coded set of instructions on how to develop into a new organism. [19] COURSE BOOK IN GENERAL BIOLOGY 6. Living things move and respond to stimuli. Higher forms of animals can transfer from one place to another. This is called locomotion. It can be done by walking, running, flying, hopping, swimming and etc. Some lower forms of animals like the sponges and corals are fixed or sessile so their movement is restricted to beating of flagella and muscular contraction. In plants, movement is even less obvious. Opening and closing of flowers, elongation of stem and roots are some of the subtle ways by which plants grow. The capability of an organism to respond to stimuli is called irritability. This depends upon the sensitivity of the organism to the stimuli. A stimulus is any chemical or physical change that causes reaction in an organism. Responses or reactions are very pronounced in animals whereas these are hardly noticed in plants. Only one plant shows a very obvious response and that is Mimosa pudica (locally known as “makahiya”). 7. Living things adapt to their environment Adaptation is a characteristic of an organism that makes it able to live in its environment. The adaptation of the fish is a structural adaptation. Conditions in an environment change from time to time. Some organisms are capable of making their body temperatures constant even when the environmental temperature changes. These [20] COURSE BOOK IN GENERAL BIOLOGY homeotherms or warm-blooded animals (man and birds) possess “built in” or physiological adaptations. On the other hand, reptiles and amphibians, which are cold -blooded or poikilotherms, lack physiological mechanisms to keep their body temperature constant. It fluctuates with the changing environmental temperature so these cold blooded animals resort to behavioral adaptations; they dig into burrows when it is warm at the surface and increase metabolism by running or hopping during cold days. Through these, they are able to regulate their body temperature. 8. Living things have life span. Life span is defined as the definite period of existence of an organism. The life span varies from one species to another. For example, some insects live only for a few hours and some for a few weeks. Some plants live for a month or more while some trees can live for over a century. Some individuals may live shorter than their life expectancy, especially when they are exposed to harsh conditions. When conditions are no longer favorable for the activities of life, then life ceases. 9. Living things have critical relationship with the environment. All organisms face a constant struggle for life. They struggle for the physical factors like water, sunlight, temperature and other requirements for maintaining life. They also struggle with other living things that could be natural enemies or competitors for the required needs for living. Struggle for existence is a problem to all living things. [21] COURSE BOOK IN GENERAL BIOLOGY [22] COURSE BOOK IN GENERAL BIOLOGY Name: ___________________________________ Score ___________ Course & Year: ___________________________ Date ____________ Exercise No. 3 Direction: Complete the table below by supplying the characteristics that distinguish plants from animals. Bases Plants Animals 1. Cell covering 2. Growth 3. Irritability 4. Reproduction 5. Metabolism Answer the following questions briefly. 1. If non living things cannot grow, how can you explain why stones increase their sizes? ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ __________________________________________________ [23] COURSE BOOK IN GENERAL BIOLOGY 2. Discuss how movement in plants differs from movements in animals. ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ __________________________________________________ 3. Explain why “Makahiya” plants close their leaves when touched or stimulated. ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ __________________________________________________ [24] COURSE BOOK IN GENERAL BIOLOGY Lesson 4. The Diversity of Life Objectives: 1. to know the modern system of nomenclature/classification of living things 2. to enumerate the characteristics of organisms belonging to the different kingdoms of life. Taxonomy is defined as the branch of biology that names and classifies species. It formalizes the hierarchical ordering of organisms accordingto characteristics such as method of feeding and cell structure. The traditional system of classification made use of only two kingdoms, Plantae and Animalia. Taxonomists later had a three-kingdom classification of living things, which included Plantae, Animalia and Monera. Much later, a five-kingdom classification included Animalia, Plantae, Fungi, Monera and Protista. Today, the Modern System of Nomenclature/Classification makes use of ten kingdoms which are: Archea(under Domain Archea), Eubacteria (under Domain Bacteria), Archezoa, Euglenozoa, Alveolata, Stramenopila, Rhodophyta, Fungi, Plantae and Animalia. Organisms under Kingdom Archezoa up to kingdom Animalia belong to Domain Eukarya. The table below shows characteristics of and some basic differences among the different kingdoms. [25] COURSE BOOK IN GENERAL BIOLOGY Table 1. Characteristics of Organisms under the Modern System of Classification Kingdom I.Archea Characteristics Lack muramic acid in their cell walls; produce distinctive lipids; different sequence of bases in their RNA molecules compared to true bacteria II.Eubacteria True bacteria; unicellular; prokaryotic; only ribosomes present in cytoplasm; with a nucleoid region containing a single circular chromosome III.Archezoa Lack mitochondria IV.Euglenozoa Include both autotrophic and heterotrophic flagellates, the euglenoids and kinetoplastids V.Alveolata Composed of photosynthetic flagellates (dinoflagellates), apicomplexans and ciliates; with small, membrane-bound cavities (alveoli) under cell surfaces VI.Stramenopila Include photosynthetic autotrophs (algae) and heterotrophs like diatoms, golden algae, brown algae and watermolds; with fine, hair-like projections on the flagella VII.Rhodophyta Red algae; multicellular; photoautotrophic; cell walls made of cellulose and other polysaccharides; no flagellated stages in their life cycle [26] COURSE BOOK IN GENERAL BIOLOGY VIII. Fungi Eukaryotic; unicellular(yeasts) and multicellular (molds, mushrooms, bracket fungi); lack chlorophyll; cell walls composed of chitin IX. Plantae Multi-cellular eukaryotes; immobile; produce food by photosynthesis; cells encased in cellulose walls; include mosses, ferns, conebearing and flowering plants X. Animalia Multi-cellular; eukaryotic; heterotrophic; include fishes, amphibians, reptiles, birds, mammals [27] COURSE BOOK IN GENERAL BIOLOGY [28] COURSE BOOK IN GENERAL BIOLOGY Name: ___________________________________ Score ___________ Course & Year: ___________________________ Date ___________ Exercise No. 4 I. Direction:Write your answer on the blank before each number. ______________1. It is a branch of biology that classifies organisms according to species. ______________2. It is a type of reproduction that involves the union of two gametes. ______________3. They are the important sources of oxygen and produce their own food through photosynthesis. ______________4. This is a kind of bacterium that is rod shaped. ______________5.These are organisms that are also known as sac fungi. ______________6.They are organisms that include flagellated microorganisms. ______________7. These are fungi that depend on decaying matter. ______________8.These are also known as the Club fungi. ______________9. They are macroscopic kinds of fungi, many of which are edible. ______________10. These are fungi that depend on livingorganisms as their host in order to live. II. True or false: Write trueif the statement is correct and false if the statement is false. Underline the word that makes the sentence false. ____________1. All bacteria are beneficial. [29] COURSE BOOK IN GENERAL BIOLOGY ____________2. Animals produce oxygen for plants. ____________3. Fungi do not contain chlorophyll. ____________4. Mushrooms are examples of fungi. ____________5. Animal cells contain cell walls. ____________6. Cells making up fungi with cell walls. ____________7. Ringworm is an example of saprophytic fungi. ____________8. Zygomycetes is one of the types of Protista. ____________9. Some fungi are good sources of antibiotics. ___________10.All organisms under Kingdom Archezoa reproduce asexually. III. Enumeration: List down three examples of organisms under each of the following kingdoms of life indicated. 1.Euglenozoa ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ 2. Stramenopila ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ 3. Fungi [30] COURSE BOOK IN GENERAL BIOLOGY ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ 4. Archezoa ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ 5. Archea ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ 6. Eubacteria ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ 7. .Flagellata ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________________ [31] COURSE BOOK IN GENERAL BIOLOGY IV. Answer the following questions briefly. 1. How does an autotrophic organism differ from a heterotrophic type of organism?? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________ 2. Why is there a need to classify organisms according to their similarities and /or differences? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________________________________ [32] COURSE BOOK IN GENERAL BIOLOGY Chapter 2 THE CHEMICAL BASIS OF LIFE [33] COURSE BOOK IN GENERAL BIOLOGY [34] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. The Composition of Living Things Objectives: 1. to discuss the chemical components that make up the bodies of living organisms 2.to determine the significance of the different chemical components in the maintenance of life Organisms are composed of matter, which is anything that occupies space and has mass and may exist as solid, liquid or gas. When matter is in its pure form, it is referred to as element. When it occurs in combination with other elements, it is a compound. Matter consists of interactions between the various chemicals making up living things. The continuous making and breaking of bonds redound to the production of characteristics manifested by living organisms. The smallest unit of an element is the atom. It consists of particles: protons (positively charged), neutrons (uncharged) and electrons (negatively charged). The chemical behavior of an atom depends on the number of electrons in the outermost shell (valence electrons). An atom with an incomplete valence shell is reactive. Atoms would chemically combine to gain stability in two ways-covalent bonding and ionic bonding- to form molecules. [35] COURSE BOOK IN GENERAL BIOLOGY A molecule’s biological function is related to its shape, which is in turn determined by the positions of its atoms’ valence orbitals. Shape is often the basis of the recognition of one biological molecule by another. The shapes of large biological molecules are reinforced by weak bonds, such as hydrogen bonds and Van Der Waals forces. They also help molecules adhere to each other. Today, about 92 natural elements are recognized by chemists, of which 25 are known to be essential in the living systems. Four elements are found in organisms in enormous amount, namely carbon (C), hydrogen (H), oxygen (O) and nitrogen (N) such that they comprise 96% of living matter. Phosphorous (P), sulfur (S), calcium (Ca), potassium (K) and few other trace elements account for the remaining 4% of an organism’s mass. Trace elements are needed only in minute quantities and the requirement differs from one species to another. Elements and Inorganic Compounds Table 2 shows the naturally occurring elements in the human body and the percentage they make up in human body weight. Table 3 presents the elements as inorganic nutrients essential for plant growth. Some elements may not form part of the organisms’ structure but are essential in carrying out specific life processes. [36] COURSE BOOK IN GENERAL BIOLOGY Table 2. Naturally Occurring Elements in the Human Body SYMBOL ELEMENT ATOMIC PERCENTAGE OF NUMBER HUMAN BODY WEIGHT O Oxygen 8 65.0 C Carbon 6 18.5 H Hydrogen 1 9.5 N Nitrogen 7 3.3 Ca Calcium 20 1.5 P Phosphorus 15 1.0 K Potassium 19 0.4 S Sulfur 16 0.3 Na Sodium 11 0.2 Cl Chlorine 17 0.2 Mg Magnesium 12 0.1 Table 3. Some Essential Inorganic Nutrients in Plants Elements Symbol Form Relevance/ Function C CO2 Major component of Macronutrients Carbon organic molecules Hydrogen H H2O Major organic [37] component of COURSE BOOK IN GENERAL BIOLOGY molecules Oxygen O O2 Major component of organic molecules Phosphorus P H2PO4- Part of nucleic acids, ATP, and phospholipids Potassium K K+ Cofactor for enzymes; water balance and opening of stomata Nitrogen N NO3- Part of nucleic acids, NH4+ proteins, chlorophyll, and coenzymes Sulfur S SO42- Part of amino acids, some coenzymes Calcium Ca Ca2+ Regulates responses to stimuli and movement of substances through plasma membrane; involved in formation and stability of cell walls [38] COURSE BOOK IN GENERAL BIOLOGY Magnesium Mg Mg2+ Part of chlorophyll; activates a number of enzymes Micronutrients Iron Fe Fe2+ Part of cytochrome needed Fe3+ for cellular respiration; activates some enzymes Boron B BO33- Role in nucleic acid B4O72- synthesis, hormone responses, and membrane function Manganese Mn Mn2+ Required for photosynthesis; activates some enzymes such as those of the Krebs cycle Copper Cu Cu2+ Part of certain enzymes, such as redox enzymes Zinc Zn Zn2+ Role in chlorophyll formation; activates some enzymes [39] COURSE BOOK IN GENERAL BIOLOGY Chlorine Cl Cl- Role in water-splitting step of photosynthesis and water balance Molybdenum Mo MoO42- Cofactor for enzyme used in nitrogen metabolism Inorganic Compounds Molecular oxygen (O2) Oxygen exists as a diatomic molecule. The atmosphere consists of about 21 percent oxygen. This is very essential to both plant and animals. Without oxygen, the cells of organisms will not be able to extract the energy from food. Carbon dioxide (CO2) is necessary for photosynthesis. It comprises .033 percent of the atmosphere. This atmospheric gas is the principal source of the principal structural element, carbon. Compared to oxygen, carbon dioxide is more soluble in water. Water (H2O) is known as the medium for life. Its abundance is a major reason why the earth is habitable. [40] Modern life, even terrestrial, COURSE BOOK IN GENERAL BIOLOGY remains tied to water. Most cells are surrounded by water, and the cells themselves are about 70 to 95 percent water. Water and its Properties Water is polar because of the unequal attraction of electrons to the elements that compose it; oxygen is more electronegative than the two hydrogen atoms attached to it, thus the opposite ends of the molecule have opposite charges. Each water molecule can hydrogen bond to a maximum of four molecules and this capability of higher level of structural organization results to the special unusual properties of water. The following properties of water are beneficial and help explain some vital phenomena in living systems. 1. High surface tension results due to the cohesive nature of water molecules. This property contributes to the transport of water against gravity in plants as it creates a “pulling effect”, that when water molecules in the leaves are transpired, they are immediately replaced by other water molecules down the xylem vessels. High surface tension also accounts for the passage of water from one cell to another by osmosis. 2. High thermal properties, specifically high specific heat and high heat of vaporization. These properties moderate heat on earth. Water stabilizes air temperatures by absorbing heat from air that is warmer and releasing the stored heat to air that is cooler. [41] COURSE BOOK IN GENERAL BIOLOGY 3. The specific heat of a substance is defined as the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1oC. Water has a specific heat of a calorie per gram per degree Celcius (1cal/g/oC). 4. Heat of vaporization is the quantity of heat a liquid must absorb for 1g of it to be converted from the liquid to the gaseous state. Compared to other liquids, water has high heat of vaporization. To evaporate each gram of water at room temperature, about 580 cal of heat are needed – nearly double the amount needed to vaporize a gram of alcohol or ammonia. 5. Water has its greatest density at 4oC and expands at higher and lower temperatures. This property makes ice float and is beneficial for organisms that thrive in bodies of water during winter season. If ice sinks, all ponds, lakes, and even oceans would eventually freeze and only the upper few inches would thaw in summer. 6. Water has high dielectric constant making it a universal solvent. Compared to other liquids, water dissolves the most number of substances. Ionic and polar substances dissolve in water. Hydrophilic substances have an affinity to water. Hydrophobic substances do not have affinity and seem to repel water. [42] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Organic Compounds in Living Things Objectives: 1.to differentiate the four classes of organic compounds found in living matter 2.to determine the significance of the different organic compounds in living things There are four classes of organic compounds in living things. These are thecarbohydrates, lipids, proteins and nucleic acids. They are also known as macromolecules because of their large size. Their synthesis is made possible by the capacity of carbon to covalently bond with itself, creating intricate molecular skeletons and joining with several other elements, producing the great diversity of organic molecules. 2.1. Carbohydrates Carbohydrates are compounds hydrogen, and oxygen. Most that carbohydrates contain are represented empirical formula Cx(H2O)y. Functions of Carbohydrates: 1. They are the immediate source of energy in organisms. 2. They also form structural units of organisms. [43] only carbon, by the COURSE BOOK IN GENERAL BIOLOGY 3. They serve as stored or reserved energy materials in organisms, in particular, the polysaccharides. 4. They may be used in the synthesis of other organic substances. Simple Sugars The basic building blocks of carbohydrates are the simple sugars or monosaccharides. These are the immediate sources of energy. Among the most important in living things are: the hexose, glucose, which exist in abundance in the blood and broken down as the source of ATP during respiration and the pentoses, ribose and deoxyribose because they form structure of RNA and DNA, respectively. Double Sugars or Disaccharides These are compound sugars composed of two simple sugars formed through a reaction called condensation reaction or dehydration reaction that involves the removal of a water molecule. Polysaccharides These are complex carbohydrates composed of many monosaccharide molecules with oxygen as bridge between the molecules. Polysaccharides are classified as digestible and indigestible based on their susceptibility to digestive enzymes. [44] COURSE BOOK IN GENERAL BIOLOGY Name _____________________________________ Score _________ Course & year ______________________________ Date __________ Exercise No. 1 I. Match the following chemical names of sugars with their common name and classify whether monosaccharide or disaccharide. A B Common Classification Name 1. glucose Fruit sugar 2. sucrose Blood sugar 3. fructose Milk sugar 4. lactose Table sugar 5. galactose Brain sugar II. Indicate the source and function of the following polysaccharides and classify whether they are digestible or indigestible Polysaccharide Source/Location Function Classificati on 1. Starch 2. Cellulose 3. Chitin 4. Glycogen 5. Insulin [45] COURSE BOOK IN GENERAL BIOLOGY 6. Pectin 2.2 Proteins Proteins are essential constituents of plant and animal protoplasm. All proteins contain C,H,O,N and sometimes S. They are far more complex than carbohydrates or lipids. They are made of building blocks called amino acids joined together by peptide linkage. An amino acid contains an amino group (NH2) and carboxyl group (COOH). When proteins are exposed to excessive heat, radiation, electricity, various chemical reagents, etc., their structure may become disorganized and normally lose their properties and activities. This type of disorganization is called denaturation. [46] COURSE BOOK IN GENERAL BIOLOGY Name __________________________________ Score___________ Course & Year ___________________________ Date___________ Exercise No. 2 I. Match the following proteins (A) with their functional classification (B). Answers may be repeated. Write the letter of your answer in the column provided for the answers. A B Answer 1. insulin a. enzyme (catalyst) 2. hemoglobin b. structural 3. actin c. regulatory 4. lactase d. transport 5. gamma globulin e. genetic 6. histones f. immune 7. casein g. contractile 8. collagen h. storage 9. sucrose 10. myoglobin II. Essay. 1.Differentiate fibrous proteins from globular proteins. Give examples of each. [47] COURSE BOOK IN GENERAL BIOLOGY 2.What make simple types of proteins different from the complex types? 3. Describe their basic structure of an amino acid. [48] COURSE BOOK IN GENERAL BIOLOGY 2.3 LIPIDS Like carbohydrates, lipids are composed principally of carbon, hydrogen and oxygen but may sometimes also contain other elements like phosphorous and nitrogen. They are insoluble in water. Lipids are important structural components of cells and they serve as fuels for energy and storage materials. Fatsare among the best known lipids. Each molecule of fat is composed of glycerol and fatty acids. Lipids primarily function as structural components of cells particularly the cell membrane, fuel for energy and as storage materials. Kinds of Lipids 1. Fats or triglycerides are the best known lipids found principally in adipose cells. 2. Waxes are found almost exclusively on surface covering in plants and in oily secretions of many insects and animals. They serve as water barriers in plants. 3. Phospholipids are composed of glycerol, fatty acids, phosphoric acid and a nitrogenous compound. They are important components of cellular membranes. 4. Steroids are complex molecules composed of four (4) interlocking rings of carbon atoms. They are very important biologically because some vitamins and hormones are steroids and they are important components of cell membranes. [49] COURSE BOOK IN GENERAL BIOLOGY [50] COURSE BOOK IN GENERAL BIOLOGY Name ___________________________________ Score____________ Course & Year____________________________ Date ____________ Exercise No. 3 Answer the following questions briefly but concisely. 1. Differentiate a saturated fat from an unsaturated fat in terms of structure, source, biological and economic importance. 2. Explain why fats are also called triglycerides. chemical components. [51] Elucidate its basic COURSE BOOK IN GENERAL BIOLOGY [52] COURSE BOOK IN GENERAL BIOLOGY 2.4 Nucleic Acids Nucleic acids are long polymers composed of building-block units called nucleotides. A nucleotide is more complex than most other small molecules since it consists of three simpler molecules in direct linkage: a nitrogenous base, a sugar residue and phosphate groups. Nucleic acids are classified into two: Deoxyribonucleic Acid (DNA), which contains the units of heredity, called genes and Ribonucleic Acid (RNA) which are of three types and function for protein synthesis. Differences between DNA and RNA Features DNA RNA Structure Double stranded Single stranded Location Nucleus Manufactured in the nucleus and goes out to the cytoplasm Function Repository of hereditary Serves as template for traits Types Sugar residue protein synthesis None mRNA, tRNA, rRNA Deoxyribose Ribose Nitrogenous Bases: Pyrimidines Purines Cytosine and Thymine Adenine and Guanine [53] Cytosine and Uracil Adenine and Guanine COURSE BOOK IN GENERAL BIOLOGY [54] COURSE BOOK IN GENERAL BIOLOGY Name _____________________________________ Score __________ Course & year ______________________________ Date __________ Exercise No. 4 Answer the following questions. 1. Illustrate the detailed structure of the DNA. How are its building blocks linked to one another? 2. In what process are the mRNAs synthesized? What material serves as template during their synthesis? [55] COURSE BOOK IN GENERAL BIOLOGY 3. What is the basic difference between a purine and a pyrimidine? [56] COURSE BOOK IN GENERAL BIOLOGY Chapter 3 CELL BIOLOGY [57] COURSE BOOK IN GENERAL BIOLOGY [58] COURSE BOOK IN GENERAL BIOLOGY Lesson 1 Cell Structure and Function Objectives: 1. to describe the different parts of plant and animal cells. 2. to state the functions of each part of the cell. The cell is the basic unit of structure and function of all living things. Cells vary in size, shape and function and are capable of basic life processes. The discoveries of scientists Robert Hooke, Matthias Schleiden and Rudolf Virchow on the cell paved the way for the development of the Cell Theory. The Cell Theory states that: Cells are the basic units of structure and function of life, and that all cells come from pre-existing cells through the process of cell division. The cell has two main regions, the outer cell body or the cytosol, containing the cytoplasm, and the inner cell body or the nucleus which contains the nucleoplasm. Although plant and animal cells may be similar to each other, a number of differences account for their uniqueness. The basic structure of a typical cell includes a cell membrane or plasma membrane but in plant cells, a cell wall is present outside this outer covering. The cytoplasm or cytoplasmic ground substance serves as the general storage and working area of the cell. It contains the following organelles: endoplasmic reticulumwhich is a winding network of membranes with channels for the transport of materials through the [59] COURSE BOOK IN GENERAL BIOLOGY cytoplasm, the mitochondria which serve as the site of cellular respiration, thegolgi apparatus which functions for the processing and packaging of cell secretions, plastids (in plant cells), which contain pigments;lysosomes, centrioles, microfilaments and microtubules (in animal cells). The nucleus controls the biochemical reactions and reproduction of the cell. It is made up of the nuclear membrane, the nucleoplasm, nucleolus and contains the chromosomes, the bearers of the cell’s hereditary units, the genes. Cells or organisms which do not have any distinct nucleus such as the bacteria including cyanobacteria are prokaryotic. Eukaryotes, on the other hand, contain sub-cellular structures enclosed by a membrane that separates them from the surrounding cytoplasm. [60] COURSE BOOK IN GENERAL BIOLOGY Name __________________________ Score ___________ Course & Year ___________________ Date ____________ Exercise No. 1 I. Write the letter of your answer on the blanks provided before each number. _____ 1. What cellular structure primarily regulates substances that move in and out of the cell? A. Cell wall B. Cell membrane C. Pinocytic vesicles D. Nuclear membrane _____ 2. What cellular component, found only in plants, bryophytes, algae and bacteria provide rigidity and strength to plant cells? A. Cell wall B. Lysosome C. Cell membrane D. Plastids _____ 3. Which of the cellular structures is considered to be responsible in directing all of the activities of the cell? A. Cell membrane B. Mitochondria C.Nucleus D. Ribosomes _____ 4. What types of organisms do not have distinct nuclei, thus have no delineation between cytoplasmic and nuclear components? A. Prokaryotes B. Eukaryotes C. Viruses D. Protozoans _____ 5. Which cellular components, found only in animal cells, contain digestive enzymes which break down large molecules of proteins, carbohydrates and fats? A.Centrioles B. Mitochondria [61] C. Lysosomes D. DNA COURSE BOOK IN GENERAL BIOLOGY _____ 6. Which type of plastids store red or brown pigments that give petals, fruits and some roots their characteristic color? A.Chromoplasts B. Amyloplasts C. Chloroplasts D. Leucoplasts _____ 7. What flexible strands take part in changing the shape of the cell, moving materials inside it, and moving the cell itself through the environment? A.Microtubules B. Microfilaments C. Cytoskeletal elements D. Endoplasmic reticulum _____ 8. What are the granular or net-like bodies within an interphase nucleus which contain the bearers of hereditary characteristics? A. Genes B. Chromatin network C. Mitochondria D. Helices _____ 9. What are the motile, whip-like extensions in many prokaryotic cells which function more like a propeller by rotating around the attachment point of the cell? A.Cilia B. Flagella C. Pseudopodia D. Chitin _____ 10. Which cell structure is responsible for cellular respiration? A. Endoplasmic reticulum C. Mitochondria B. Golgi apparatus D. Plastids II. Matching Type. Match Column A (shape of cell) with Column B (areas of the human body) and write the letter of your choice on the blanks provided before each number. A B _____ 1. Cuboidal A. Small intestines [62] COURSE BOOK IN GENERAL BIOLOGY _____ 2.Stellate B. RBC of man _____ 3. Amorphous C. Cardiac muscle cells _____ 4. Columnar D. Human bone cells _____ 5.Circular E. Nervous tissue cells _____ 6. Fusiform F. Smooth muscle cells _____ 7. Net-like G. Surface cells of the skin _____ 8. Spider-like H. Kidney tubules _____ 9. Squamous I. ova or egg cells _____10.Spherical J. White blood cells K. Blood platelets L. Cells of the stomach [63] COURSE BOOK IN GENERAL BIOLOGY [64] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Cell Division Objectives: 1. to describe the various stages of mitosis and meiosis in plant and animal cells 2. to show the significance of cell division among organisms Mitosis is the type of cell division that maintains the parental number of chromosome sets in each daughter nucleus. The products generated after the process are two similar daughter cells and a number of chromosomes which is specific for every species of organism. This process is responsible for growth, development, repair of body tissues and the transmission of hereditary characteristics of the organism. A cell undergoes to major phases/periods during mitosis: an interphase period, where materials needed for the succeeding stages are synthesized, and an M-Phase or Period of Division. The M-phase includes a) prophase, where the nucleus disintegrates and chromosomes thicken and shorten; b) metaphase, involving the alignment of each chromosome at the center of the equatorial plane; c) anaphase where chromatids of every chromosome split from each other and move to opposite poles, and d) telophase, where two similar daughter cells having the same chromosomal number as the original cell are produced through cleavage furrow formation in animal cells and in plant cells, through cell plate formation. Meiosis, on the other hand, is a special cellular division resulting in the reduction of the original chromosome number by half. This type of cell [65] COURSE BOOK IN GENERAL BIOLOGY division is involved in the formation of sex cells or gametes. The diploid condition is restored when two gametes unite in fertilization. There are two phases involved in meiosis: Meiosis I or Reduction Division, and Meiosis II or Equational Division. Meiosis I results in the production of two similar daughter cells each of which has a chromosomal number one half of the original cell. This resulting chromosomal number is due to the separation of chromosomes at anaphase I which have previously aligned themselves by pair at the center of the equatorial plane during metaphase I. On the other hand, Meiosis II produces from one cell, a total of four daughter cells each of which contains a chromosomal number similar to its parent cell. This is similar to what happens in mitosis where the chromosomal number of the parent cell is maintained in each of the daughter cells. [66] COURSE BOOK IN GENERAL BIOLOGY Name _______________________________ Score _________ Course &Year ________________________ Date__________ Exercise No. 2 I. Give the correct sequence of events/processes during Mitosis by numbering I, II…V the events listed below, where I is the earliest event and V, the last event. Write your answers on the space provided before each event. . _______ 1.Chromosomes orient themselves along the center of the equatorial plane. _______2.Chromosomes undergo the process of replication. _______3.Chromosomes split/separate from each other as sister chromatids and migrate to their respective poles. _______4.The cell membrane either forms cleavage furrows (in animal cells) or cell plate (in plant cells) to produce two identical daughter cells. _______5.The chromatids of each chromosome continue to thicken and shorten, the nucleolus becomes smaller, and the nuclear membrane starts to disintegrate. [67] COURSE BOOK IN GENERAL BIOLOGY A. Meiosis II. Direction: Match the stage of meiosis with the corresponding events that occur during that particular stage. Write the letter of the correct answer on the line provided before each number. A B _____ 1. Chromosomes align at the A. Prophase I spindle _____ 2.Homologous chromosomes separateB. Metaphase I and move to opposite poles _____ 3. Sister chromatids separate and move C. Anaphase I to opposite poles _____ 4. Crossing-over occurs between non- D. Telophase I sister chromatids of each homologous pair _____ 5. Each daughter nucleus ends up with E. Prophase II one set of chromosomes _____ 6.Homologous pairs of chromosomes F. Metaphase II align at spindle equator _____ 7. One set of chromosomes is clustered G. Anaphase II at each of the two spindle poles _____ 8. Spindle is rearranged into two spindles, one for each chromosome parcel [68] H. Telophase II COURSE BOOK IN GENERAL BIOLOGY Lesson 3. Gametogenesis Objectives: 1. to discuss the role of meiosis in the production of new species 2. to illustrate gametogenesis in plants and animals Reproduction gives the assurance that organisms continue producing new offspring and thus continue perpetuating the species. Every species undergoes a life cycle with cell division playing a significant role in the production of new species. Sexual reproduction involves two parents, each of which contributes sex cells or gametes. The union of the egg and the sperm will develop into a new individual. This union results in genetic variations among offspring. Asexual reproduction involves only one parent and no sex cells are present. Each organism is capable of producing identical copies of itself. In animals, gametogenesis, the production of sex cells, occurs through Spermatogenesis (in males), and Oogenesis (in females). Spermatogenesis occurs in the male gonads/testes and comprises steps or changes leading to the production of mature male gametes or sperm cells. Four spermatozoa are formed per primary spermatocyte. Oogenesis, on the other hand, occurs in the female gonads/ovaries and comprises steps leading to the production of females gametes/eggs. The result is the formation of one egg and three non-functional polar bodies. Thus, from one primordial egg cell, four ova are produced, all haploid. [69] COURSE BOOK IN GENERAL BIOLOGY In plants, gametogenesis occurs through microsporogenesis (in the male) or megasporogenesis (in the female). Microsporogenesis involves the production of microspores or pollen grains (when encapsulated), all haploid in the anther of a staminate flower. Megasporogenesis, on the other hand, produces megaspores, likewise all haploid, in the ovary of a pistillate flower. When one sperm nucleus in the pollen tube unites with an egg nucleus in the ovary, a diploid embryo is formed which would mark the beginning of a new sporocyte. The other sperm nucleus unites with the two polar nuclei found in the ovary, producing a triploid endosperm. This in essence, results to double fertilization. [70] COURSE BOOK IN GENERAL BIOLOGY Name _____________________________ Score __________ Course & Year _____________________ Date __________ Exercise No. 1 I.Direction: Determine the chromosomal number of the following cells at stages of mitosis/meiosis or gametogenesis as indicated. Place your answer on the line provided before each number. ______ 1. Anaphase 1 in a primary spermatocyte ______ 2. leaf epidermal cell ______ 3. Endosperm cell ______ 4. Early telophase in a skin cell ______ 5. Primary oocyte ______ 6. Secondary spermatocyte ______ 7. Megaspore ______ 8. Egg nucleus ______ 9. Spermatid ______ 10.primordial egg cell ______ 11.generative nucleus in a pollen tube ______ 12.microspore mother cell ______13.antipodal nucleus ______14.anaphase II in a secondary oocyte ______15.ootid [71] COURSE BOOK IN GENERAL BIOLOGY [72] COURSE BOOK IN GENERAL BIOLOGY Name __________________________ Score ___________ Course& Year ___________________ Date ___________ Exercise No. 2 Problem Solving 1. Corn (Zea mays) is a flowering plant with a somatic chromosome number of 20. How many of each of the following will be present in one somatic cell at the stage listed? ______ a. Centromeres at prophase ______ b. Centromeres at anaphase ______ c. Chromatids at prophase ______ d. Chromosomes at anaphase ______ e. Chromosomes at telophase II ______ f. Chromosomes at telophase I ______ g. centromeres at anaphase I ______ h. Chromatids at late anaphase 2. How many human eggs will be formed from ______ a. 40 primary oocytes ______ b. 40 secondary oocytes ______ c. 40 ootids 3. How many human sperms will be formed from ______ a. 40 primary spermatocytes ______ b. 40 secondary spermatocytes [73] COURSE BOOK IN GENERAL BIOLOGY ______ c. 40 primordial sperm cells 4. How many of the following would be produced if a flowering plant has twenty six microsporocytes? ______ a. Microspores ______ b. Sperms ______ c. Generative nuclei 5. How many of the following would be expected to be produced if there are ten megasporocytes? ______ a. Megaspores ______ b. Polar nuclei ______ c. Synergids [74] COURSE BOOK IN GENERAL BIOLOGY Chapter 4 ENERGY AND METABOLISM [75] COURSE BOOK IN GENERAL BIOLOGY [76] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. Metabolism Objectives: 1. to define metabolism and energy 2. to discuss the importance of metabolism to the biological world 3. to differentiate anabolism and catabolism Activities of living things require energy, the ability to do work or bring about a change. Organisms are capable of survival and maintenance because of continuous acquisition and expenditure of energy. The ultimate source of energy on earth is the sun. Plants are able to trap and utilize this solar energy when they make food through the process of photosynthesis. Animals, on the other hand, get energy when they feed on plants or other animals that have eaten plants. This energy stored in the chemical bonds of organic molecules is released through the process of cellular respiration. In order to function, the cells must harvest the energy stored in the bonds of food molecules and use it to power and control the countless chemical reactions that make life possible. The sum total of all chemical processes for the maintenance of life is called metabolism. It has two components which are opposing activities, anabolism and catabolism. The constant expenditure of energy (catabolism) demands a corresponding intake of energy by the cell for restorative purposes (anabolism). [77] COURSE BOOK IN GENERAL BIOLOGY Photosynthesis and respiration are examples of generally opposing metabolic activities. Photosynthesis is an anabolic process of building up organic materials from carbon dioxide and water, both inorganic in nature. Respiration, on the other hand, is a catabolic process of breaking down these organic materials into carbon dioxide and water. The former takes place in the chloroplasts of plants while the latter takes place in the mitochondria of cells. Energy may be stored in many organic molecules, in particular, carbohydrates such as sugars and starches, which are called food molecules. The most common food molecule is the sugar, glucose. A cell may have a large supply of energy stored in the chemical bonds of sugars, however, it cannot use them directly to fuel its energy-requiring processes. Initially, it must transfer the energy from its sugar molecules to a substance called adenosine triphosphate, or ATP. It is aptly known as the universal energy currency in living things because it is the principal form of energy that is usable by cells of all organisms. When the cell has extra energy, it can be stored in ATP. This energy can easily be released from the ATP later. When the cell needs energy, it breaks the last phosphate bond, thus liberating the energy that holds the second and third phosphates together. When the last phosphate bond is broken, the molecule of ATP becomes a molecule of adenosine diphosphate (ADP) and a molecule of phosphate (P). The reaction can be expressed by the following equation. ATP ADP + P + energy The double arrows indicate that the reaction is reversible. [78] COURSE BOOK IN GENERAL BIOLOGY Energy in living systems is governed by the physical laws of thermodynamics as follows: The first law states that the energy of the universe is constant; it can be transferred and transformed but it cannot be created or destroyed. Total energy is always conserved. The second law states that thenatural tendency of the universe is to wards increasing disorder.The total degree of randomness naturally tends to increase and energy is converted to less organized form. The measure of energy for the performance of work is free energy, also referred to as Gibbs free energy (G). Work must be done in order to attain the state of equilibrium. The displacement of a reaction from or towards equilibrium is denoted by ∆G, free energy change. Based on this, reactions could be classified into: a. Endergonic reaction which is any process moving away from equilibrium. It consumes energy and results to products that contain more free energy than the reactants. In this case, ∆G is positive; b. Exergonic reaction, any process going toward equilibrium. It releases energy and results to products that contain less free energy than the reactants. In this case, ∆G is negative. The transfer of electrons from a donor to an acceptor molecule as influenced by the redox potential or free energy change in electrochemical [79] COURSE BOOK IN GENERAL BIOLOGY units play a vital role in oxidation-reduction reactions that take place in metabolic processes like photosynthesis and respiration. The continuous synthesis and degradation of molecules and substances in the cell during metabolism involves biological catalysts, called enzymes. These are proteins which speed up biological reactions by lowering the amount of activation energy, a unit of energy needed to start a reaction, or destabilize the reactants’ existing chemical bonds. [80] COURSE BOOK IN GENERAL BIOLOGY Name:___________________________________ Course/Year/Section:___________________ Score: _____________ Date: _____________ Exercise No. 1 I. Classify the following processes as anabolism or catabolism bychecking the appropriate column in the table below. Process Anabolism Catabolism Digestion Respiration Photosynthesis Glycogenesis Glycogenolysis Lipolysis Deamination Fermentation II. Answer the following questions briefly. A. How important is metabolism? _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ [81] COURSE BOOK IN GENERAL BIOLOGY _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ ______ B. Discuss the role of energy in the bodies of living things. _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ ______ [82] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Chloroplasts and Photosynthesis Objectives: 1. to describe the chloroplasts 2. to discuss the process of photosynthesis 3. to show the relationship between the Light Reaction Phase and the Dark Reaction Phase of photosynthesis. Photosynthesis is a process by which chlorophyll-bearing plants manufacture food for themselves and all other living things. When photosynthesis occurs, carbon dioxide is absorbed and oxygen is released. In plants, the main organ for photosynthesis is the leaf, which contains organelles in their mesophyll cells called the chloroplasts. These are bounded by two separate membranes, each composed of a lipid bilayer. A chloroplast contains a gel-like substance called the stroma. An extensive system of internal membranes form disc-shaped structures, called the thylakoids. In appressed regions, these are referred to as granal thylakoids (grana lamellae) and in non-appressed regions, they are called stromal thylakoids (stroma lamellae). The cavity or lumen of the thylakoid is filled with water and dissolved salts. Essentially, there are two main compartments of the chloroplast that function for photosynthesis; the stroma and the grana. The stroma contains the enzymes necessary for the reduction of carbon dioxide into carbohydrates. The grana, on the other hand, contain chlorophyll and other pigments that are involved in the capture of light energy. The chlorophyll pigments absorb maximum light at the blue and red regions, while accessory [83] COURSE BOOK IN GENERAL BIOLOGY pigments absorb the violet, orange and yellow regions. The yellow green and green regions are reflected or transmitted, hence the green color of the leaves. The overall process of photosynthesis can be divided into two phases, the light reaction and the dark reaction which are compartmentalized in the grana and the stroma, respectively, as summarized in the following illustration. Figure 1. The Light and Dark Reactions of photosynthesis [84] COURSE BOOK IN GENERAL BIOLOGY The Light Phase The light reaction occurs in the thylakoid membrane of the chloroplast, which contains photosystems or light harvesting units (PS II and PS I) that cooperate to generate chemical compounds, ATP and NADPH. The photosystems contain pigments and proteins that vary in their redox potentials. When energy from the sun is absorbed, electrons are excited in activated pigments, such as chlorophyll, and they are passed on to a pigment or non-pigment acceptor along a gradient of redox potentials. In the process of photosynthetic electron transfer, energy is released and captured for the generation of ATP. ATP is produced via cyclic photophosphorylation and noncyclic photophosphorylation. During the light phase, water is oxidized (photolysis of water), split into electrons, protons and molecular oxygen. The electrons are passed along the electron transport system. In the non-cylic electron flow, nicotinamide adenine dinucleotide phosphate (NADP) is the ultimate acceptor of electrons, thus reduced to become NADPH. The protons (H +) contribute to the pH gradient across the thylakoid membrane that serves as the driving force for the synthesis of ATP. Molecular oxygen is evolved as gas. The two relatively energy-rich compounds produced during the light phase, ATP and NADPH, are subsequently used in the dark phase of photosynthesis. The Dark Phase The dark reaction is the second phase that occurs in the stroma of the chloroplast. It is the primary process by which inorganic carbon is converted [85] COURSE BOOK IN GENERAL BIOLOGY into organic compounds making use of the high energy phosphate bonds of ATP and the redox energy of NADPH. In the Calvin Cycle, CO2 is initially fixed or accepted by a 5-C compound, ribulose- 1,5 bisphoshate (RuBP) via a carboxylating reaction catalyzed by the enzyme ribulose bisphosphate carboxylase oxygenase (Rubisco). This reaction yields two moles of 3-Phosphoglyceric acid (PGA), the first stable product from which the Calvin Cycle’s other name, C3 Cycle, is derived. The subsequent reactions lead to the production of intermediates and the regeneration of the CO2 acceptor, ribulose-1,5 bisphosphate to ensure the continuous operation of the cycle. The fixation of one molecule of CO2 requires an input of 3 ATP and 2 NADPH from the light phase. The production of one molecule of the 3-carbon product of the cycle, glyceraldehyde-3-phosphate (G3P) or triosephosphate (TP) requires three turns of the cycle. This compound is the starting material for the synthesis of organic compounds, primarily sugars and more complex carbohydrates. The general equation for the process of photosynthesis is as follows: 6 CO2+ 6 H2O → C6H12O6+ 6 O2 [86] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________ Score:___________ Course/Year/Section: _______________ Date:____________ Exercise No. 1 Write the correct letter of your choice on the space provided for. ____1. Which of the following are the raw materials for photosynthesis? A. H2O +O2 B. H2O + CO2 C. O2 + CO2 D. C6H12O6 + H2O ____2. Plants appear green because A. they absorb green light B. they reflect green light C. they contain carotenoids D. they undergo photosynthesis ____ 3. In the light reaction phase, which raw material is oxidized or split? A. water B. oxygen C. glucose D. carbon dioxide ______ 4. At the end of the dark reaction, which of the following sugars is formed? A. Glyceraldehyde 3- Phosphate (G3P) B. sucrose [87] COURSE BOOK IN GENERAL BIOLOGY C. glucose D. fructose _____5. When water molecule splits during photolysis, which molecule is released as gas? A. ATP B. water C. oxygen D. carbon dioxide _____6. Which of the following are pigments used by plants to absorb sunlight? A. chlorophyll B. phycobillins C. xanthophylls D. all of the above _____7. Which of the following is not true about the light reactions of photosynthesis? A. ATP is the product of light reactions. B. The light reactions occur at daytime. C. The light reactions need chlorophyll molecules. D. Carbon dioxide is a raw material in the light reactions. _____8. Light reaction of photosynthesis occurs in A. the lumen of the thylakoid B. stroma [88] COURSE BOOK IN GENERAL BIOLOGY C. outer membrane of the chloroplast D. thylakoid membrane of the chloroplast ____9.In photosynthesis, energy is stored in the form of A. ATP B. water C. oxygen D. carbon dioxide _____10. The role of the accessory pigments is to A. allow the generation of ATP in the dark reaction B. capture additional energy and transfer it to the chlorophyll reaction centers C. allow photosynthesis to occur in the dark reaction and provide an additional pigment to generate more ATP D. donate electrons to chlorophyll reaction centers and prevent photophosphorylation _____11. Photosynthesis is measured in the leaf of a green plant exposed to different wavelengths of light. Photosynthesis is A. highest in red light B. highest in blue light C. highest in green light D. highest in red and blue light _____12. The first event in photosynthesis is A. reflection of light B. deflection of light [89] COURSE BOOK IN GENERAL BIOLOGY C. absorption of light D. refraction of the light ______ 13. Where does carbon fixation occur? A. chloroplast stroma B. in the lumen or cavity of the thylakoid discs C. in the intermembrane space of chloroplast D. within the thylakoid membranes ______14. Which of the following enzymes is responsible for CO2 fixation in C3 plants? A. Phosphoenol pyruvate carboxylase B. hexokinase C. succinate dehydrogenase D. ribulose bisphosphate carboxylase/oxygenase (rubisco) _______15. Which of the following is not correct about ATP formation in photosynthesis? A. It is a product of photophosphorylation. B. It is driven by proton or pH gradient. C. It takes place during the photosynthetic carbon reduction (PCR) cycle. D. It occurs when energy is available to link Pi with ADP. [90] COURSE BOOK IN GENERAL BIOLOGY Name:___________________________________ Score: _____________ Course/Year/Section:___________________ Date: _____________ Exercise No. 2 Direction: Identify the phase of photosynthesis (Light phase or dark phase) being described or the phase to which the following reaction or compounds are associated. Write I – if light phase, II – if dark phase ________ 1. ATP and NADPH produced ________ 2. Photolysis of water ________ 3. Chlorophyll and accessory pigments are necessary ________ 4. Use of ribulose bisphosphate carboxylase/oxygenase ________ 5. Oxygen is produced ________ 6. Takes place in the grana ________ 7. Takes place in the stroma ________ 8. Carbon dioxide combines with ribulose- 1,5 bisphoshate (RuBP) ________ 9. Accumulation of protons in the lumen of the thylakoid ________ 10. Reduction of 3-phosphoglycerate into glyceraldehyde-3-P phosphate [91] COURSE BOOK IN GENERAL BIOLOGY [92] COURSE BOOK IN GENERAL BIOLOGY Name:___________________________________ Course/Year/Section:___________________ Score: _____________ Date: _____________ Exercise No. 3 I. Complete the table below by differentiating the light reaction of photosynthesis from the dark reaction phase based on the following: Light reaction phase Dark phase Site Important components of the site Source of energy Raw materials Products By-products [93] reaction COURSE BOOK IN GENERAL BIOLOGY II. Discuss briefly the two phases of photosynthesis. [94] COURSE BOOK IN GENERAL BIOLOGY Lesson 3. The Mitochondrion and Cellular Respiration Objectives: 1. to describe the mitochondrion and its role in cellular respiration 2. to discuss the various stages of cellular respiration 3. to differentiate photosynthesis from respiration. Cellular respiration is a very important metabolic process which takes place in both plants and animals. It provides continuous supply of energy for the sustenance of life. This process entails the conversion of chemical energy in food such as glucose and other organic molecules, into its usable form, Adenosine Triphosphate (ATP). The chemical equation that describes respiration is as follows: C6H12O6 + 6O2 6CO2 + 6H2O + energy (ATP) Cellular respiration takes place in specialized organelles, the mitochondria (Fig. 2) suspended in the cytosol of cells. They are small, measuring 0.5 to 10 micrometers (μm) in diameter. Every mitochondrion is bounded by a double membrane consisting of phospholipid bilayer. The outermost membrane is smooth while the inner membrane is extensively folded into cristae to increase the available surface area. It contains the components of the electron transport chain and the enzymes for the synthesis of ATP. [95] COURSE BOOK IN GENERAL BIOLOGY The double membranes divide the mitochondrion into two distinct compartments; the intermembrane space and the mitochondrial matrix. The intermembrane space is the narrow part between the two membranes while the mitochondrial matrix is the part enclosed by the innermost membrane. The matrix is filled with dense fluid containing the enzymes needed for the Kreb’s cycle. Like the chloroplasts, mitochondria are semiautonomous in that they have their own DNA and ribosomes and can divide and grow to make more of themselves. The mitochondria are called the “powerhouses” of the cell because they generate most of the supply of adenosine triphosphate (ATP), the cell’s energy currency. Fig 2. A diagram of an animal mitochondrion (Source: http://biology.about.com/od/cellanatomy/ss/mitochondria.htm) The three stages of cellular respiration are Glycolysis, Tricarboxylic Acid (TCA) cycle or Kreb’s cycle and the Electron Transport system (ETS). These are shown in the illustration below. [96] COURSE BOOK IN GENERAL BIOLOGY Fig 3. The phases of complete glucose breakdown (Source: Mader, S.S. 2004. Biology.8th Edition. McGraw. Hill Book Co. USA. p 133) Glycolysis takes place in the cytoplasm of the cell and does not require oxygen, thus the process is anaerobic. The Krebs cycle and the Electron Transport System occur in the matrix and along the cristae, respectively and require oxygen, thus they are aerobic in nature. Glycolysis Glycolysis literally means the degradation of sugar, specifically, the degradation of a 6-C sugar (hexose) such as glucose into pyruvic acid. Complex organic molecules like starch, sucrose and maltose have to be digested or hydrolyzed into hexose through enzyme-catalyzed reactions before they could undergo glycolysis. The splitting or hydrolysis of hexose requires an initial input of energy which is provided by the expenditure of two ATP molecules by the cell. [97] COURSE BOOK IN GENERAL BIOLOGY During the partial degradation of a molecule of hexose in the cytoplasm, two molecules of pyruvic acid are formed, and two molecules of nicotinamide adenine dinucleotide (NAD) is reduced to NADH. A total of four ATP are synthesized through substrate level phosphorylation, resulting to a net gain of two ATP. In this stage O2 is not utilized and no CO2 is produced. The pyruvic acid produced can be oxidized later in the mitochondrion to yield more ATP. Likewise, the NADH molecules will be passed on to the electron transport system to completely extract the energy that they contain. Glycolysis also produces intermediates that can be utilized for the synthesis of other substances needed by the organism. Further oxidation of pyruvic acid or pyruvate requires oxygen. When oxygen is limiting, the extraction of energy will not be completed and instead leads to the accumulation of pyruvate and NADH resulting to fermentation, producing ethanol or lactic acid. Fermentation is an enzyme-catalyzed reaction. Pyruvic acid decarboxylase and alcohol dehydrogenase are involved in alcoholic fermentation, whereas, lactic acid dehydrogenase is required in lactic acid fermentation. Fermentative metabolism provides continuous supply of NAD+ needed in glycolysis, however, it releases only a very small fraction of the available energy from the substrate. Kreb’s Cycle (Citric acid cycle/Tricarboxylic acid cycle) When oxygen is available, the pyruvate diffuses into the mitochondrial matrix where a transition reaction occurs that serves to prepare [98] COURSE BOOK IN GENERAL BIOLOGY pyruvic acid before entering the Krebs cycle. This involves the oxidation of pyruvate into acetic acid (2C compound). CO2 is formed when the detached carbon reacts with oxygen. Two molecules of NADH are generated during this preparatory process. Acetic acid combines with coenzyme A to form acetyl CoA, which enters the Kreb’s cycle and reacts with oxaloacetic acid (4C) forming the first stable product, citric acid, from which the process or cycle is also named. During the cycle, organic acid intermediates are formed (Fig. 4C), followed by oxidation of these intermediates and transfer of electrons (and protons) to NAD and FAD, forming NADH and FADH2, respectively. Fig 4. The Krebs Cycle (Source:http://schoolworkhelper.net/wp-content/uploads /2011/02/kerb-cycle.jpg) [99] COURSE BOOK IN GENERAL BIOLOGY In the Krebs cycle, four CO2 molecules are released, two ATP are directly synthesized by substrate level phosphorylation and six NADH and two FADH2 (which are subsequently oxidized to yield ATP along the electron transport system) are produced from the two molecules of acetic acid that entered the cycle. In this stage of cellular respiration, the oxidation of hexose (glucose) to CO2 is completed. Through the Kreb’s cycle, carbon skeletons for the synthesis of certain amino acids are formed, providing building blocks for proteins and other larger molecules. Electron Transport System The electron transport system (ETS) provides for an avenue for the complete extraction of ATP from the oxidation of energy-rich compounds NADH and FADH2. Electrons are passed on to electron carriers, consisting of four major protein complexes in the inner mitochondrial membrane (Fig 4d). Oxygen serves as the ultimate electron acceptor and reduced to water. This water is released from the cell as a waste product. Fig 5. The Electron Transport Chain [100] COURSE BOOK IN GENERAL BIOLOGY (Source: http://schoolworkhelper.net/wp-content/uploads/2011/02/electrontransport-2chain.jpg) As the electrons are passed along the chains of electron carriers, they gradually lose energy and the released energy pumps protons (H+) into the intermembrane space, creating a proton or pH gradient across the membrane. This gradient (proton motive force) serves as the driving force for the synthesis of ATP from ADP and Pi, catalyzed by ATP synthase. ATP formation within the electron transport system of aerobic respiration is called oxidative phosphorylation. At the completion of glycolysis and aerobic respiration, glucose has been broken down into carbon dioxide and water, and energy has been released. Table 4a shows the ATP generated from the various stages of cellular respiration. For every molecule of glucose that is broken down in glycolysis and respiration, 38 molecules of ATP are formed. Since glycolysis requires an initial input of two molecules of ATP, the cell has a net gain of 36 ATP from the complete oxidation of a glucose molecule. Table 1. ATP yield from the complete oxidation of glucose Stage ATP/Electron donor ATP Yield to ETS Glycolysis Krebs Cycle (including 2NADH 2 ATP 2 ATP 2NADH x 2 ATP [101] 4 ATP COURSE BOOK IN GENERAL BIOLOGY transition (glycolysis) reaction) 8 NADH x 3 ATP Electron Transport 24 ATP (Kreb’s Cycle) 2 FADH2 x 2 ATP 4 ATP (Kreb’s Cycle) Total: 36 ATP Fig 6 presents a general overview of the entire process of cellular respiration. Fig 6. Diagram of cellular respiration (Source: http://www.bukisa.com/articles/30849_diagram-of-cellular-respiration) [102] COURSE BOOK IN GENERAL BIOLOGY Table 2. Comparison between Photosynthesis and Respiration Photosynthesis Respiration 1. takes in carbon dioxide 1. releases carbon dioxide 2. releases oxygen 2. binds oxygen 3. synthesizes sugars and other 3. degrades sugars and organic compounds other organic compounds 4. results in increase in dry weight 4. results in decrease in weight 5. occurs only in the presence of 5. occurs in all living cells chlorophyll 6. stores energy 6. releases energy 7. occurs only when light energy is 7. occurs throughout the available entire life of any cell 8. H is transferred from H2O to 8. H is transferred from food NADP to NAD [103] COURSE BOOK IN GENERAL BIOLOGY [104] COURSE BOOK IN GENERAL BIOLOGY Name:___________________________________ Course/Year/Section:______________________ Score: _____________ Date: _____________ Exercise No. 1 Direction: Write the correct letter on the space provided for. ____1. Which of the following would happen to the stored energy in food when living cells break down food molecules? A. stored as ADP B. stored as ATP C. released as heat D. Both b and c ____2. Which of the following stages in cellular respiration produces the greatest amount of ATP? A. glycolysis B. the Krebs cycle C. lactic acid fermentation D. the electron transport chain ____3.The following are stages of respiration except one. Which is this? A. glycolysis B. the Krebs cycle C. the Calvin cycle D. electron transport ____4.Which of the following refers to the breakdown of food molecules to harness ATP? [105] COURSE BOOK IN GENERAL BIOLOGY A. photosynthesis B. cellular respiration C. alcoholic fermentation D. lactic-acid fermentation ____5. Which stage in cellular respiration produces citric acid? A. glycolysis. B. the Krebs cycle C. carbon fixation D. the electron transport chain. ____6.Which of the choices below is not a characteristic of a mitochondrion? A. It is a small organelle suspended in the cytoplasm of prokaryotes. B.It is a small, threadlike or sausage-shaped organelle. C. It is an organelle in eukaryotic cells D. It can divide, making more of itself. ____7.Which of the following is required in order for aerobic respiration to take place? A. water B. oxygen C. sunlight D. carbon dioxide ____8. Which would happen when muscles are exercised extensively in the absence of sufficient oxygen? [106] COURSE BOOK IN GENERAL BIOLOGY A. NADH molecules split B. lactic acid is produced C. oxidative respiration occurs D. a large amount of ATP is formed ____9. In which of the following organelles/compartments will the initial phase of respiration take place? A. lysosome. B. cytoplasm C. mitochondria D. endoplasmic reticulum ____10.Which of the processes below correctly represents the equation :6 CO2+ 6 H2O → C6H12O6+ 6 O2 A.fermentation B.photosynthesis. C.cellular respiration D. protein breakdown ____11. Which of the following refers to “molecule A” in the equation: C6 H12O6 + 6O2 = 6CO2 + 6 H2O + MOLECULE A? A. ATP B. ADP C. NADPH D. NADH ____12.Which process describes the action of yeast on the production of alcohol and CO2? [107] COURSE BOOK IN GENERAL BIOLOGY A. glycolysis B. aerobic respiration C. alcoholic fermentation D. lactic acid fermentation ____13.Which of the following processes involves the conversion of pyruvic acid to carbon dioxide and ethanol? A. glycolysis B. gasohol conversion C. alcoholic fermentation D. lactic acid fermentation ____14.Which of the following describes mitochondria as the “power house” of the cell? A. They utilize the ATPs of the cell. B. They produce the cell’s supply of energy. C. They store the energy in the form of ATPs. D. They trap solar energy in order to produce ATP. ____15. In which of the following areas does glycolysis occur? A. in the nucleus of the cell B. outside the mitochondria C. in the matrix of the mitochondria D. in the cristae of the mitochondria ____16.Which of the following is the final and most important product of cellular respiration? A. water [108] COURSE BOOK IN GENERAL BIOLOGY B. carbon dioxide C. 2 pyruvic acids D. adenosine triphosphate ____17.Which process does not happen inside the mitochondrial matrix? A. citric acid cycle B. oxidation of glucose C. oxidation of pyruvate D. production of ATP with ATP synthase ____18.Which of the following is the product of glycolysis? A. PGAL B. acetyl CoA C. lactic acid D. pyruvic acid ____19.Which of the following describes glycolysis? A. it produces glucose B. it is an anaerobic process C. it produces four ATP molecules D. it produces four ADP molecules ____20.Which products of the Krebs Cycle donate their electrons along the electron transport chain? A. H2O and CO2 B. NADH and FADH2 C. acetyl CoA and ATP D. oxaloacetic acid and citric acid [109] COURSE BOOK IN GENERAL BIOLOGY [110] COURSE BOOK IN GENERAL BIOLOGY Name:___________________________________ Score: _____________ Course/Year/Section:___________________ Date: _____________ Exercise No. 2 I.Direction: Complete the process of cellular respiration by filling the blanks with the correct words/phrases. Glycolysis Glycolysis literally means 1)__________-splitting." In glycolysis, the 2)______-carbon sugar glucose is split into 3)________ molecules of pyruvate, also called 4)___________acid. This process produces a net gain of 5)________ATP molecules. The resulting molecules of pyruvate each have 6)_________carbon atoms. Glycolysis takes place in the cell's 7)_______________. The remainder of cellular respiration takes place in organelles called 8)________________. The Krebs Cycle The Krebs Cycle takes place in the fluid-filled area inside the inner membrane of the mitochondria known as the 9)_____________ The gas 10)___________________ is a byproduct of this process. The Electron Transport Chain Most of the11)__________is produced in this last step of cellular respiration. Electron transport takes place in the infoldings of the innermembrane of the 12)_____________. mitochondria. At These the transport,13)_____________combines infoldings end with hydrogen 14)______________(e-) to form 15)______________ . [111] of are called electron ions and COURSE BOOK IN GENERAL BIOLOGY ½O2 + 2H+ + 2e- → H2O Overall Process glucose + oxygen → carbon dioxide + water + 38 (16)________ Fermentation In the absence of 17)_________________, the cell resorts to anaerobic metabolism. In animal cells, pyruvate is converted to 18)___________acid. In yeast and bacteria, the pyruvate is often converted to 19)_______________ . In both cases, no new ATP is produced, so the net production of the20)_______________ -carrying molecule consist only only of themolecules of ATP produced in glycolysis. II. Direction: Fill out the following table to differentiate respiration from photosynthesis Respiration Reactants Site of reaction By-products Products [112] Photosynthesis COURSE BOOK IN GENERAL BIOLOGY Chapter 5 FUNCTIONAL ORGANIZATION IN PLANTS [113] COURSE BOOK IN GENERAL BIOLOGY [114] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. Plant Tissues Objectives 1. to identify the different types of plant tissues. 2. to describe the locations and functions of the different tissue systems in land plants. There are two types of plant tissues: meristematic and permanent. Meristematic tissues are growth tissues while permanent tissues are mature and differentiated tissues. There are three main types of meristematic tissues in vascular seed plants: apical, intercalary, and lateral meristems. Permanent tissues are mature and differentiated tissues that can be surface or dermal tissues, fundamental tissues and vascular tissues. Meristematic Tissues (Embryonic Tissues) Apical meristems are found on the tips of growing stemsand roots. These are responsible for the increase in length of the plant body and the production of leaves. There are also meristematic areas toward the periphery of the roots and stems, and these lateral meristems are responsible for the increase in diameter of the plant. Some monocots, such as grasses & bamboo, have intercalary meristems located above the bases of leaves and stems allowing them to regrow quickly after being cut down. [115] COURSE BOOK IN GENERAL BIOLOGY Permanent Tissues 1. Simple Tissues are fundamental tissues composed of cells similar in structure or function. These are made up of the following: a. Parenchyma–These are considered as one of the most common and most abundant plant tissues. They are usually thin-walled and composed of closely packed cells that may function in photosynthesis, food or water storage. b. Collenchyma - These are cells with unevenly thickened cell walls which function primarily for support. c. Sclerenchyma – These are cells with uniformly thickened walls which function also for support. Most of them are dead cells. a. Parenchyma b. Collenchyma c. Sclerenchyma (Adopted from Audesirk & Audesirk, 1998) [116] COURSE BOOK IN GENERAL BIOLOGY 2. Complex tissues are made up of different types of cells which work together as a unit to carry out one or more specific functions. They may be: a. Vascular – These are concerned with transport of materials in the plant body. There are two types of vascular tissues: xylem and phloem. The xylem (common name is wood) conducts water and dissolved substances from the roots to the leaves of the plant. The phloem mainly conveys food materials from the leaves to the different parts of the plant. b. Dermal tissues form the protective outer covering of the plant body. These are made up of the following parts: 1). Epidermis.These tissues are often flattened, one-cell thick and often irregular in shape located on the surface of roots, stems and leaves. The epidermis aids in protection against water loss, mechanical injury, and invasion by parasites. 2). Periderm.The periderm replaces the epidermis as the stems and the roots of plants increase in diameter. It provides protection while permitting gas exchange. This waterproof tissue becomes the cork or outer bark of an old tree. [117] COURSE BOOK IN GENERAL BIOLOGY [118] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________________Score: ____________ Course & Year ___________________________ Date: ____________ Exercise No. 1 I. Fill-in the table below with the required information. Types of Tissues Location I. Meristematic tissues 1. Apical 2. Lateral 3. Intercalary II. Permanent tissues 1. Dermal 2. Fundamental/ground [119] Function COURSE BOOK IN GENERAL BIOLOGY 3. Vascular II. Matching Type. A. Match each of the tissues below with a permanent tissue or embryonic tissue from the answer list. Any answer may be used once, more than once, or not at all. Write your choice on the space provided before each number. Answer List ____________________1. Parenchyma a. dermal tissue ____________________2. Epidermis b. ground tissue ____________________3. Xylem c. vascular tissue ____________________4. Periderm d. apical meristem ____________________5. Collenchyma e. lateral meristem ____________________6. Vascular cambium ____________________7. Phloem ____________________8. Root hairs ____________________9. Pericycle ____________________10. Cork cambium ____________________11. Buds of shoot [120] COURSE BOOK IN GENERAL BIOLOGY ____________________12. Root zone of cell division ____________________13. Leaf stomata ____________________14. Mesophyll ____________________15. Leaf vein B. Match each item with its function. Write the letter of your answer onthe space provided. _____________________16. Periderm cell a. waterproofs stem and leaf _____________________17. Tracheid b. absorption of water by root _____________________18. Phloem cell c. support, hardened with lignin _____________________19. Parenchyma d. water and mineral transport _____________________20. Sclerenchyma e. serves as outer area of bark _____________________21. Cuticle f. protective shoot covering _____________________22. Epidermis g. sugar transport _____________________23. Casparian Strip h. storage and photosynthesis _____________________24. Root hair i. waterproofs endodermis _____________________25. Apical j. for longitudinal growth Meristem [121] COURSE BOOK IN GENERAL BIOLOGY [122] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. The Plant Body Objectives 1. to cite the importance of plants. 2. to identify the organs and organ systems of a plant body. 3. to explain the general functions of plant organ systems. A plant has two organ systems: 1) the shoot system, and 2) the root system. The shoot system is above ground and includes the organs such as leaves, buds, stems, flowers (if the plant has any), and fruits (if the plant has any). The root system includes those parts of the plant below ground, such as the roots, tubers, and rhizomes. shoot system root system Fig 1.The Plant Body. (Adopted from Herren, R.V., 1997) [123] COURSE BOOK IN GENERAL BIOLOGY [124] COURSE BOOK IN GENERAL BIOLOGY Name: ________________________________ Course & Year ____________________________ Score: ____________ Date: ____________ Exercise No. 1 I. Answer the question as required. Look around you and reflect for a moment on all the products and “services” supplied by plants. On the space below, list five specific examples from your surroundings illustrating how we use plants. Name the plants if you can. [125] COURSE BOOK IN GENERAL BIOLOGY II.Answer the following questions briefly. 1. What are the general functions of the root system? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 2. What are the general functions of the shoot system? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 3. How do the root and shoot systems complement each other to maintain the normal function of the plant body? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ [126] COURSE BOOK IN GENERAL BIOLOGY Lesson 3. Functional Organization of the Root Objectives: 1. to identify the different types of roots according to origin and morphology 2. to determine the microscopic structure of the root 3. to explain the functional organization of the roo The root is generally a non-green underground plant organ used for absorption of raw materials and for anchorage of the plant. True roots originate from the tip of the hypocotyl of the embryo. Roots have the following main functions: a. absorption of water and minerals- by osmosis, imbibition, diffusion, and active absorption b. conduction of absorbed materials and food c. anchorage of the plant in the soil d. storage of food (starch, sucrose) in the cortex, phloem and xylem Types of Roots as to Origin 1. Primary roots. These are the roots derived from the main trunk 2. Secondary roots. These are roots that arise from the primary roots. 3. Adventitious roots. These are roots that arise from other plant parts. Types of Roots as to Morphology 1. Tap root system. This is made up of a main root which grows and sends out lateral branches. [127] COURSE BOOK IN GENERAL BIOLOGY 2. Diffuse or fibrous root system. This is composed of a primary root which stops growing or disappears, and numerous adventitious roots which grow and develop from the base of the stem and take the place of the primary root. This root system may be of the fibrous or fleshy type. Fig. 1.A longitudinal section of a typical root tip. Microscopic Structure of Roots Longitudinal section of a young root 1. Root Cap. This thimble-shaped mass of moderate-sized cells forms the apex of the root and protects the meristematic (dividing) cells just above it. The outer layer of cells is continually sloughed off to be replaced by newly formed root cap cells. 2.Meristematic Region. This area comprises a mass of small, nearly cubical cells with thin walls and dense protoplasm. It is the region where new cells are formed by mitosis. It is responsible for the increase in length of roots. [128] COURSE BOOK IN GENERAL BIOLOGY 3. Elongation Region. In this region, the cells formed in the meristematic region undergo rapid enlargement, new protoplasm is formed and vacuoles increase in size. 4. Region of Maturation (Differentiation). – This region is situated above the region of elongation. The enlarged cells become differentiated into the mature tissues of the root - xylem, phloem, etc. 5. Root hairs are produced in the younger part of the maturation region. These are projections of epidermal cells and serve to increase the absorbing surface and anchor the growing tip of the root. Fig. 7.Cross section of a root through the region of maturation. Cross-Section of a Root Through the Region of Maturation 1. Epidermis. This is the surface layer of cells that produces the root hairs and thus is an absorptive tissue as well as a tissue that furnishes protection to underlying cells. 2. Cortex. This region comprises somewhat irregular-shaped parenchyma cells with many intercellular spaces. It is chiefly a waterand food-storage region. The innermost cell layer of the cortex is the endodermis, which usually has its inner and sidewalls thickened with [129] COURSE BOOK IN GENERAL BIOLOGY suberin, a waterproof material. The endodermis functions as a dam which prevents the outward passage of water from tissues inside the endodermis. The endodermal cells are composed of: a) Casparian strips. These are endodermal cells of the roots with thick bands found on the outside of the phloem and which prevent the outward passage of water from tissues inside the endodermis. b) Passage cells. These are endodermal cells with thin walls, and located on the outside of the xylem. 3. Stele. (Central Cylinder) This is the innermost region. The xylem and phloem are observed to be alternate in arrangement. a. Pericycle. This is the outermost tissue of the vascular cylinder, and consists of one layer of small thin-walled cells within the endodermis. It gives rise to branch roots which force their way out through the cortex and epidermis. b. Xylem. This is a complex tissue with parenchyma, sclerenchyma fibers and transparent cells (xylem vessels). They form a group of thick-walled cells arranged in radial rows and altered with thin-walled phloem cells. As seen in cross-section, the xylem is usually arranged in the form of a star. Xylem tissues conduct water and nutrient ions toward the stems. [130] COURSE BOOK IN GENERAL BIOLOGY c. Phloem. The phloem is composed mainly of very small thinwalled cells which alternate with the xylem rays. The phloem consists of parenchyma cells, sieve-tubes and companion cells. These complex tissues function to transport food in the form of sugars and amino acids to the different parts of the plant body. [131] COURSE BOOK IN GENERAL BIOLOGY [132] COURSE BOOK IN GENERAL BIOLOGY Name: ________________________________ Course & Year __________________________ Score: ____________ Date: ____________ Exercise No. 1 I. Answer the following questions briefly. 1. What are other specialized functions of roots? Give specific examples of plants with specialized functions of their roots. ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 2. Give three examples each of plants with tap root system and fibrous root system. ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 3. How doprimary, secondary and adventitious roots differ from each other? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ [133] COURSE BOOK IN GENERAL BIOLOGY 4. What is the function of root hairs? ________________________________________________________ ________________________________________________________ ________________________________________________________ ____________________________________________ [134] COURSE BOOK IN GENERAL BIOLOGY Lesson 4. Functional Organization of the Stem Objectives: 1. to identify the external and internal parts of a stem 2. to explain the function of the stem 3. to describe the functional organization of stem The first stem of a seed plant develops from a part of the seed embryo known as the epicotyl. A stem with its leaves is termed a shoot. All the stems, branches and leaves constitute its shoot system. Most stems grow above the ground (aerial stems) while some grow underground (subterranean stems). External Structure of Stems 1. Node. It is the slightly enlarged portion of the stem where leaves and buds arise. 2. Internode. It is the region of the stem between the two successive nodes. 3. Lenticel. This is a tiny raised pore on the surface of matured stems for gas exchange. 4. Scars. These are marks left on the stem such as leaf scar, bundle scar, bud scar, fruit scar, flower scar and twig scar. 5. Buds. These are undeveloped shoots. Largely meristematic tissue buds may be classified as follows: a. terminal and axillary buds b. naked buds and covered buds c. active buds and dormant buds d. flower buds, leaf buds, mixed buds e. alternate buds [135] COURSE BOOK IN GENERAL BIOLOGY Fig. 1.External structure of a stem. (Adopted from Audesirk & Audesirk, 1998) Internal Structure of the Stem 1. Epidermis. This is the outermost part of the stem consisting of a single layer of cells with thick outer wall. Hairs or trichomes may or may not be present. 2. Cortex. This is the region next to the epidermis. It consists of: Collenchyma. This is made up of three or more layers of cells with thick walls at the corner located toward the inner part. a) Parenchyma. These are two or more layers of cells with thin walls located toward the inner part. b) Endodermis or starch sheath. This is the innermost layer of the parenchyma which contains numerous starch grains 3. Stele. This structure occupies the rest of the regions of the stem within the cortex. It consists of the following parts: [136] COURSE BOOK IN GENERAL BIOLOGY a) Pericycle. This is made up of alternate layers of thick-walled sclerenchyma cells and thin-walled parenchyma cells. b) Vascular bundles. These are distinct groups of cells arranged in the form of a ring in dicot stems and scattered in monocot stems. Each bundle is divided into: Xylem. This is the region of vascular bundles located toward the center of the stem; complex tissues which conduct water and nutrient ions toward the stems Phloem. This is the region of the vascular bundle located toward the periphery and consisting of thin-walled cells; it functions to transport food in the form of sugars and amino acids to the different parts of the plant body. Cambium. This is the region of the vascular bundle located between the xylem and the phloem and is made up of a layer of small, thin-walled and tangentially elongated cells. Pith or medulla. This is the central part of the stem and composed of thin-walled parenchyma cells. Pith rays or medullary rays. These are the regions between the vascular bundles, connecting the pith with the pericycle. They are thin-walled, radially elongated parenchyma cells. [137] COURSE BOOK IN GENERAL BIOLOGY Fig. 2. Internal Structure of a stem (cross section): (a) monocot stem (b) dicot stem (c) youn00g woody stem [138] COURSE BOOK IN GENERAL BIOLOGY Name: ____________________________________ Score: ____________ Course & Year ____________________________ Date: ____________ Exercise No. 1 Direction: Answer the following questions briefly. 1. What are the major and specialized functions of the stem? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 2. How do monocot stems differ from dicot stems? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ [139] COURSE BOOK IN GENERAL BIOLOGY [140] COURSE BOOK IN GENERAL BIOLOGY Lesson 5. Functional Organization of the Leaf Objectives: 1. to classify the different types of leaves and shapes as to bases, tips and margins 2. to identify the external and internal structure of the leaf. 3. to explain the function of the leaf 4. to describe the functional organization of stems The leaf is the lateral outgrowth of the stem and is typically thin, expanded, and green in color. The major functions of the leaf are photosynthesis and transpiration. It also performs other specialized functions. External Structure of the Leaf A typical leaf (Fig. 1) consists of a stalk, or petiole and expanded part, the blade. In many leaves, small flaps of tissue, the stipules, grow out from the base of the petiole. Sessileleaves lack petioles. Fig. 1.External structure of a leaf. [141] COURSE BOOK IN GENERAL BIOLOGY Leaves may be simple or compound: simple leaves have a single subdivision or leaflet, compound leaves have more than one leaflet. Fig. 2. Types of leaves (Adopted from Herren, R.V., 1997) Leaves are also classified according to their arrangement on the stem There are three different leaf arrangements (Fig. 3): alternate (one leaf per node), opposite (two leaves per node) and whorled (three or more leaves per node). [142] COURSE BOOK IN GENERAL BIOLOGY Fig. 3.Leaf Arrangement. (Adopted from Herren, R.V., 1997) Leaves are also identified by shape. They come in an assortment of shapes, margin and venation. Internal Structure of the Leaf (fig. 4) 1. Epidermis. This is usually a single layer of cells on the upper and lower surfaces of the leaf. The upper epidermis of most leaves has thicker cuticle and fewer stomata than the lower. The cells fit tightly together and are of two types: a) Ordinary epidermal cells:They often secrete a waxy cutin. The water-proof cutin layer, or cuticle, is effective in reducing water loss. The ordinary epidermal cells protect the inner tissues from desiccation, mechanical injury, and parasites. [143] COURSE BOOK IN GENERAL BIOLOGY b) Guard cells. These are paired, crescent-shaped cells containing chloroplasts and control the opening and closing of the stomata. 2. Mesophyll .This occupies the portion of the leaf between the upper and lower epidermis. It is the photosynthetic layer of the leaf. It has two distinct layers: a) Palisade layer. This consists of elongated, cylindrical parenchyma cells adjacent to the upper epidermis. b) Spongy layer. This consists of irregular-shaped and loosely arranged cells. 3. Veins. These are terminals of a vascular system which extend from the root to the leaf and function for conduction of water, minerals and organic substances including food. They also serve for strengthening and support. Fig 4.Internal structure of a leaf. [144] COURSE BOOK IN GENERAL BIOLOGY Name: _____________________________ Score: ____________ Course & Year ___________________ Date: ____________ Exercise No. 1 Direction: Answerthe following briefly. 1. What are other specialized functions of the leaf? Give specific examples. ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 2. What structures regulate water loss and CO2 absorption by a leaf? How are these processes regulated? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ 3. What structure secretes a waxy cuticle that prevents water loss? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ [145] COURSE BOOK IN GENERAL BIOLOGY 4. How does the lower epidermis differ from the upper epidermis? ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________________________ [146] COURSE BOOK IN GENERAL BIOLOGY Lesson 6. Functional Organization of the Flower Objectives: 1. to identify the structures that make up a typical flower 2. to determine the functions of the different parts of a flower 3. to know the different types of flowers The flower is a highly specialized shoot adapted to carry on sexual reproduction and the production of seeds. Structure of the Flower 1. Floral envelope or Perianth. a. Corolla. This is composed of petals.They function to attract insects or small birds which carry pollen from one flower to another. b. Calyx. This part is composed of green, leaf-like parts called sepals which protect the inner parts of the flower. c. Floral stalk or pedicel d. Receptacle or torus – the expanded portion of the stalk [147] COURSE BOOK IN GENERAL BIOLOGY 1. Essential Organs a. Pistil (or carpel). This is usually found at the center of the flower. It consists of the following: 1. Stigma, the enlarged portion, usually moist, where pollen grains adhere 2. Style, the long, slender structure which holds the stigma 3. Ovary, the enlarged basal part of the pistil which develops into a fruit. The cavities are called locules which contain the ovules or undeveloped seeds. b. Stamen - consists of the following parts: 1. Anther, the enlarged structure where pollen grains are produced 2. Filament, the thread-like stalk that holds the anther Kinds of Flowers A. As to parts present 1. Complete flowercontains all parts of the floral envelope and the essential organs 2. Incomplete flowerlacks any part of the floral envelope or essential organs B. As to shape or form 1. Regular flower has parts or sets of organs of similar shape and size 2. Irregular flower has some parts or sets of parts of different shape or size [148] COURSE BOOK IN GENERAL BIOLOGY C. As to essential parts 1. Perfect flowerhas both stamen and pistil 2. Imperfect flower is one with either pistil or stamen A monoecious plant has both the staminate and pistillate flowers in same plant. A dioecious plant has the staminate flower in one plant and pistillate flower in another plant. [149] COURSE BOOK IN GENERAL BIOLOGY [150] COURSE BOOK IN GENERAL BIOLOGY Name: ____________________________________ Score: ____________ Course &Year ___________________________ Date: ____________ Exercise No. 1 Answer the following questions briefly. 1. What are the accessory parts of a flower? ________________________________________________________ ________________________________________________________ ________________________________________________________ ______________________________ 2. Why are these parts called accessory? ________________________________________________________ ________________________________________________________ ________________________________________________________ ______________________________ 3. What are the essential parts of a flower? ________________________________________________________ ________________________________________________________ ________________________________________________________ ______________________________ [151] COURSE BOOK IN GENERAL BIOLOGY 4. Why are they considered essential parts? ________________________________________________________ ________________________________________________________ ________________________________________________________ ______________________________ [152] COURSE BOOK IN GENERAL BIOLOGY Chapter 6 FUNCTIONAL ORGANIZATION IN ANIMALS [153] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. Animal Tissues Objectives: 1. to identify the different tissues that make up the animal body 2. to determine the characteristics of the different animal tissues 3. to discuss the functions of each of the different types of tissues Animal organization becomes more complex with increasing number of cells. Multicellular animals are more complex and have greater capacity for internal specialization than unicellular organizations. There are four main categories of tissues found in multicellular animals: epithelial tissues, connective tissues, nervous tissues, and muscle tissues. Epithelial Tissues Epithelial tissues are the most widely distributed tissues that cover the external and internal surfaces of the body. The cells making up these tissues are closely connected together by small amounts of intercellular substances between and among them. The cells are also usually arranged in thin, compact layers and are often supported below by a basement membrane. Cells composing epithelial tissues may be flat (squamous), cube-shaped (cuboidal), or elongated (columnar)(fig.1). Epithelial cells can be simple or stratified. Simple epithelium has only a single cell layer. Stratified epithelium has more than one layer of cells. [154] COURSE BOOK IN GENERAL BIOLOGY The functions of epithelial tissues include protection, absorption, secretion and sensation. Squamous Cells Basement membrane Cuboidal Columnar Figure 1.Shapes of epithelial tissues. Connective tissues Connective tissues are composed of cells widely separated from each other and scattered through a non-living extracellular matrix. This matrix is composed of two regions: ground, which may be liquid, gel-like or solid, and fiber, which maybe elastic or non-elastic. Connective tissues bind and connect together the different tissues, filling the spaces between them. They do not form compact masses like the epithelial tissues and they have a large amount of intercellular material between cells. [155] COURSE BOOK IN GENERAL BIOLOGY There are different types of connective tissues (Fig. 2). These are loose (areolar) connective tissues, dense (fibrous) connective tissues, adipose tissues, cartilages, bone tissues, and blood. Fig. 2.Types of connective tissues. Muscle Tissues Muscles are the primary units of motion which perform mechanical work by contraction because of the presence of contractile elements or fibers known as the myofibrils. Muscle tissues are composed of these fibers specialized for contraction. They facilitate movement of animals by contraction of individual muscle cells. In hollow organs of the body, they are responsible in pushing or transporting substances from one area to another. Three types of muscles (Fig. 3) occur in animals: skeletal (striated) muscles, smooth muscles, and cardiac muscles. Skeletal muscles are long [156] COURSE BOOK IN GENERAL BIOLOGY and gradually taper at the ends. They have sarcoplasmic myofibrils, with each myofibril consisting of myofilaments. These myofilaments possess two contractile elements, actin and myosin. Skeletal muscles are voluntary muscles attached to the bones via the tendons and are responsible for motion and different body movements. Smooth muscles are spindle or fusiformshaped and are non-striated. They are found in most hollow organs and are involuntary in nature. Cardiac muscles, on the other hand, are the muscles of the heart. They consist of net-like cells and have myofibrils with crossstriations. Cardiac muscles are likewise involuntary since they contract automatically and rhythmically Fig 3. Types of muscle tissues Nervous Tissues [157] COURSE BOOK IN GENERAL BIOLOGY Nervous tissues consist of two main cell types: neurons and glial cells. The neuron (Fig.4) which is the functional unit of the nervous system, transmits nerve impulses. On the other hand, glial cells, which are connective tissue cells, are in direct contact with neurons and often surround them. Nervous tissues respond to stimuli and transmit impulses from one body part to another. The synapse is the point of contact of two nerve cells. A neuron is composed of the following parts: cell body, and cell processes – the axon and dendrite. The cell body contains the nucleus, mitochondria and other organelles typical of eukaryotic cells. The axon is usually a long, single process whose main function is to carry impulses away from the cell body. Dendrites, which are shorter expansions from the cell body, are usually multiple and function to carry impulses towards the cell body. Figure 4.Organization of a neuron. (image adapted from Purves et. Al. Life: The Science of Biology, 4th Editi [158] COURSE BOOK IN GENERAL BIOLOGY Name: ____________________________________ Course & Year: ___________________________ Score: ___________ Date: ___________ Exercise No. 1 Fill in the table below with the appropriate word/phrase. Muscle Tissues Location Distinguishing Characteristics 1. Epithelial Tissues a. squamous epithelium b. cuboidal epithelium c. columnar epithelium 2. Connective Tissues a. loose (areolar) [159] Function/s COURSE BOOK IN GENERAL BIOLOGY connective tissue b. dense connective tissue c. adipose d. cartilage e. bone f. blood [160] COURSE BOOK IN GENERAL BIOLOGY 3. Muscle Tissues a. skeletal muscle b. cardiac muscle c. striated muscle 4. Nervous Tissues [161] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Organ Systems The bodies of animals are made up of various body systems -groups of organs that work together to perform particular or related functions. An organ system consists of a group of organs that perform intricate functions necessary for the survival of an organism. It is the most complex organization in the animal’s body. There are eleven major organ systems making up animals, although some animals lack one or more of them. The major systems composing the human body are the following: integumentary system, skeletal system, muscular system, nervous system, endocrine system, cardiovascular/circulatory system, lymphatic system,respiratory system, digestive system, urinary/excretory system, and reproductive system. [162] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.1. Integumentary System Objectives: 1. to identify the structure and functions of the skin. 2. to determine variations in skin structure and function in animals. 3. to know the relationship of skin structure and function. The integumentary system is the largest organ system in terms of volume. It forms the external covering of the chordate body. This system comprises the skin, its pigments, and various exocrine glands that produce sweat, tears, sebum and other oils, mucous, waxes, scents, and milk. In humans, this system accounts for about 16 percent of total body weight and covers 1.5-2m2 of surface area. The integumentary system includes all derived structures such as hair, feathers, scales, teeth, baleen, nails, claws, horns, beaks, and hooves. This system performs the following functions in promoting homeostasis of the body: 1. It protects the body against abrupt changes in the weather and helps to regulate temperature 2. It provides a front line of defense against foreign invaders 3. It restricts the movement of fluids leaving and entering the body 4. It provides coloration and protection from the sun with skin pigments [163] COURSE BOOK IN GENERAL BIOLOGY 5. It houses sensory receptors, which inform the brain of external stimuli 6. It helps excrete waste materials through perspiration 7. It provides for gaseous exchange (respiration) 8. It cushions and protects vital organs 9. It generates vitamin D through exposure to ultraviolet light 10. It stores water, fat, and vitamin D Structure of the Skin The skin is composed of two layers of tissue: the epidermis and the dermis. The epidermis is an epithelial tissue while the dermis is the connective tissue layer. Beneath the dermis is a loose connective tissue called the hypodermis or subcutaneous layer. [164] COURSE BOOK IN GENERAL BIOLOGY Figure: 1. Skin Structure (Source: MyDelicateSkin.com) Epidermis The epidermis mainly functions for protection, absorption of nutrients, and homeostasis. It consists of a keratinized stratified squamous epithelium that is made up of keratinocytes which produce keratin, melanocytes which produce melanin, Langerhans' cells which work with other cells to fight foreign bodies andMerkel cells. [165] COURSE BOOK IN GENERAL BIOLOGY Four to five layers of cells make up the epidermis. Starting from the bottom, these layers are as follows: stratum basale,stratum spinosum,stratum granulosum,stratum lucidum, and the stratum corneum. The stratum basale is the only layer capable of cell division, pushing up cells to replenish the outer layer in a process called terminal differentiation. The stratum corneum is the most superficial layer and is made up of dead cells, proteins, and glycolipids. Figure 1.2. The Epidermis (Source: /www.ratbehavior.org) Dermis The dermis is composed of dense (fibrous) connective tissue. It is made up of major regions – the papillary and reticular areas that vary in thickness in response to the function they serve. [166] COURSE BOOK IN GENERAL BIOLOGY The papillary layer is the upper dermal area that has fingerlike projections on its superior surface called dermal papillae. This layer houses the pain receptors (free nerve endings) and touch receptors (Meissner’s corpuscles). The reticular layer, the deepest skin layer, contains the blood vessels, sweat and oil gland, and deep pressure receptors, the Pacinian corpuscles. Subcutaneous layer (hypodermis, or superficial fascia) This is the layer of tissue directly underneath the dermis. It is composed mainly of adipose tissue or fatty tissue. [167] COURSE BOOK IN GENERAL BIOLOGY [168] COURSE BOOK IN GENERAL BIOLOGY Name __________________________________ Score ___________ Course & Year _________________________ Date ____________ Exercise No. 2 1. Identification. Give a particular structure in the skin that make/s the following functions possible. The first one is made as an example for your guidance. Function of the Skin Structure/s that perform/s the function 1. Provides protection against Melanocytes UV radiation produce pigment 2. Regulates body temperature 3. Provides coloration 4. Cushions and protects vital organs 5. Helps excrete waste materials through perspiration 6. Provides for gaseous [169] the that melanin COURSE BOOK IN GENERAL BIOLOGY exchange (respiration) 7. Serves to feel the changes in the surroundings. 8. Serves to waterproof the skin 9. Provides a front line of defense against foreign invaders 10. Protects the body from dehydration 2. Fill in the table below by giving the importance of the following skin glands in animals. Skin glands Importance 1. Uropygial glands in birds 2. Ceruminous glands in the ear canal [170] COURSE BOOK IN GENERAL BIOLOGY 3. Mammary glands 4. Lacrimal glands 5. Scent dogs glands and in other animals 3. Identification. Give the structures/appendages derived from the skin of the following animals. 1. Whales ______________________________________________ 2. Birds ________________________________________________ 3. Tiger ________________________________________________ 4. Pigs _________________________________________________ 5. Man _________________________________________________ [171] COURSE BOOK IN GENERAL BIOLOGY [172] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.2. The Digestive System Objectives: 1. to compare the organization and structure of the digestive system in various animals 2. to identify the parts and function of each part of the digestive system 3. to discuss the processes of digestion 4. to describe the role of accessory organs and glands in the digestion process Parts of the Digestive System The digestive system is composed of the digestive tract, accessory organs and accessory glands. The digestive tract, which is about nine meters in man, is the tube where food passes. It starts from the anterior end, the mouth cavity, to the pharynx, esophagus, stomach, small intestine, and large intestine. The accessory organs and glands play important roles in digestion. These are the liver, gall bladder, pancreas and salivary glands. The Digestion Process Digestion can be divided into two phases: mechanical and chemical phases. By mechanical digestion, the food is broken down into smaller [173] COURSE BOOK IN GENERAL BIOLOGY pieces by teeth. The food is moistened and softened by the saliva produced by the salivary glands. The tongue manipulates the food during chewing and helps shape the food into a ball called a bolus. Chemical digestion is the further breakdown of food molecules by the action of digestive enzymes. Enzymes in the saliva called salivary amylase perform the initial breakdown of starch in the mouth to form smaller polysaccharides. In the stomach, the gastric juice containing pepsin initially breaks down proteins into smaller polypeptides for complete digestion to amino acids in the small intestine. The small intestine contains digestive juices from the pancreas, liver, gall bladder, and intestinal glands. Pancreatic enzymes include protein-digesting enzymes, proteases to produce amino acids, amylases to further digest sugar to disaccharides, and DNA and RNA to nucleotides. Digestion proceeds through peristalsis, the wavelike contraction of the digestive tract that moves the mixture of chyme and digestive juices along the digestive tract. The products of digestion cross the linings of the small intestine through the process called absorption. Amino acids and sugars pass through the epithelium, enter capillaries and are carried away from the intestine by the bloodstream. Molecules of fatty acids and glycerol on the other hand, diffuse from the epithelial cells to the lacteals and reach the lymph. The undigested food or feces in the large intestines are excreted out from the body. Before the feces are removed, they are acted upon by bacteria, one of which is Escherichia coli. [174] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________ Date: ____________ Course: _________________________ Score: ___________ Exercise No. 3 I. Essay. Answer the following questions briefly: 1. What are the variations of the digestive system in animals? What must have caused these variations? __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ ________________ 2. How do animals prevent the digestion of their own cells and tissues? ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________ II. Matching type: Match the following parts of the digestive system to the activities taking place, or the functions they perform. ____1.where food is chewed and swallowed [175] a. Stomach COURSE BOOK IN GENERAL BIOLOGY ____2.where final digestion of foodstuff b. Mouth takes place ____3. Elimination of feces takes place here. c. .Large intestine ____4.produces the bile d. Liver ____5.turns big foodstuff to smaller pieces e. Pancreas ____6.responsible for the re-absorption f.. Gall of water bladder g. Teeth ____7. It stores the bile. h.Small intestine ____8. Where final products of digestion i.Salivary are absorbed glands ____9.secretes both digestive enzymes j. Anus and hormones ___10.secretes serous and mucous substances into the mouth k. pharynx l.esophagus ___11. Passageway of food, water and air ___12. Chyme is formed in this organ. ___13.the passage of food and water to the stomach ___14.where ingestion of food takes place ___15.where protein digestion starts IV. Complete the table below [176] COURSE BOOK IN GENERAL BIOLOGY Digestive Food Stuff Organ Mouth Starch Stomach Proteins Enzyme Source of secreted Enzyme Product α-amylase Gastric glands Small Starch α-amylase intestine Lactose Maltase Sucrose Intestinal glands Fats Lipase Polypeptides V. From the final site of digestion, trace the pathway of the following products of digestion until they are ready for circulation. Use a diagram to show this. [177] COURSE BOOK IN GENERAL BIOLOGY a. Glucose b. Fatty acids and glycerol c. Amino acids [178] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.3. Skeletal System Objectives: 1. to identify the different types of skeletal systems in animals 2. to know the structures and functions of the skeletal system 3. to locate and identify the important bones and joints in the animal’s body The skeleton is the firm framework of the body. It provides physical support and protection and provides surfaces for attachment of muscles. It also functions in blood cell formation, maintenance of mineral homeostasis, storage of fats and minerals and serves as a leverage of the animal body to facilitate movement. Skeletal systems are commonly divided into three types—external (an exoskeleton), internal (an endoskeleton), and fluid based (a hydrostatic skeleton), although hydrostatic skeletal systems may be classified separately from the other two, because they lack hardened support structures. The endoskeleton consists of rigid or semi-rigid structures movement of which is made possible by the muscular system. If the structures are mineralized or ossified, as they are in humans and other mammals, they are referred to as bones. Cartilage is another common component of skeletal systems, supporting and supplementing the skeleton. Some organisms have a skeleton consisting entirely of cartilage and without any calcified bones at all, as in sharks. The bones or other rigid structures are connected by ligaments and connected to the muscular [179] COURSE BOOK IN GENERAL BIOLOGY systemvia tendons. The vertebrate skeleton consists of the axial skeleton (skull, vertebral column, and associated structures) and appendicular skeleton (limbs or appendages. The axial skeleton supports and protects the organs of the head, neck, and torso, and in humans, it comprises the skull, ear ossicles, hyoid bone, vertebral column, and rib cage.The appendicular skeletoncomprises the pectoral and pelvic limb girdles and bones of the free appendages. The girdles provide a supporting base onto which the usually mobile limbs attach. [180] COURSE BOOK IN GENERAL BIOLOGY Name _______________________________ Course & Year ______________________ Score __________ Date ___________ Exercise No. 1 I. .Fill in the blanks with the correct answer. 1. The ___________________ connect muscles to the bones while the ________________ help hold bones together where they meet at joints. 2. The __________________ is the only moveable bone attached to the skull and provides for chewing motion. 3. The ribs, breast bone and vertebral column form the _________________ cage which provides protection to the heart and the lungs. 4. The ________________________ type of skeleton forms joints with the axial portion at the shoulders and hips. 5. The vertebral column is composed of _____________________ irregularly-shaped bones. 6. The coccyx is located at the _______________________ of the vertebral column. 7. Tarsals are the bones of the ____________________________. [181] COURSE BOOK IN GENERAL BIOLOGY 8. The _________________________ is the longest, largest and strongest bone of the body. 9. The ______________________ are the points of contact between bones or between cartilages and bone where all changes in the position of bony parts occur. 10. The ____________________ or kneecap is a large, sesamoid bone which protects the knee joint and strengthens the tendons that form the knees. II.Essay. Answer the following questions briefly: 1. How many bones make up the human skull? Of these, how many form the cranium, the facial bones and the middle-ear bones? ______________________________________________________________ ____________________________________________________________ ______________________________________________________________ ______________________________________________________________ ____________________ 2. What are the components of the human vertebral column? Give the number of bones that make up each of these components. ______________________________________________________________ ______________________________________________________________ [182] COURSE BOOK IN GENERAL BIOLOGY ______________________________________________________________ ______________________________ 3. Distinguish compact (dense bone) from spongy (cancellous bone). ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________ 4.What are joints? Identify the different types of joints. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________ III. The following are the general classifications of bones. Provide the necessary information by filling up the table below as to their location and distinguishing feature/s: Classification of Location Bone 1. Distinguishing Feature Long bones 2. Short bones 3. Flat bones [183] COURSE BOOK IN GENERAL BIOLOGY 4. Irregular bones 5. Sesamoid bones [184] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.4. Nervous System Objectives: 1. to identify the structures and functions of the nervous system 2. to determine the significance of the nervous system 3. to discuss human disorders related to the nervous system 4. to show the significance of the nervous system in the general integrity of human functions Thenervous system functions for impulse conduction and acts as a coordinator or “director” of the various organ systems.Without this coordination, the physiological processes taking place within the body would work in a haphazard way. The body’s nervous system is able to do this because of the presence of nervous tissues that are highly specialized and exhibit two distinct properties: irritability and conductivity. They are able to perceive, receive, respond to stimuli and conduct them to various parts of the body. The human nervous system is divided into two interrelated parts: the Central Nervous System consisting of the brain and the spinal cord, and the Peripheral Nervous System which includes all nerves which connect the periphery, that is, muscles, glands, visceral organs and receptor organs, to and from the Central Nervous System. The brain isthe enlarged anterior end of thespinal cord. The ratio between the weight of the brain and the spinal cord affords a fair criterion of an animal’s intelligence. The brain is considered the largest and most [185] COURSE BOOK IN GENERAL BIOLOGY complex mass of nervous tissue found in the body and is divisible into five distinct parts: telencephalon, diencephalon, mesencephalon, metencephalon and the myelencephalon, whose most important part is the medullaoblongata. Nerves enter and leave the brain in the same manner as the nerves of the spinal cord. The spinal cord is located within the spinal canal of the vertebral column. It begins superiorly at the brain (particularly at the medulla) and ends inferiorly in the conus medularis and a fine thread called the filum teminale. It has two major portions: the innermost gray matter and the outer white matter. [186] COURSE BOOK IN GENERAL BIOLOGY Name __________________________________ Score ________ Course & Year __________________________ Date _________ Exercise No. 1 I. Fill in the table below as to the function and location of the following types of receptors. Type of Receptor Function Location Mechanoreceptors Thermoreceptors Chemoreceptors Photoreceptors II. Fill in the table below as to the nature, function and distribution of the following Cranial Nerves [187] COURSE BOOK IN GENERAL BIOLOGY Number Name Nature Function Distribut ion 1 Olfactory 2 Optic 3 Oculomotor 4 Trochlear 5 Trigeminal 6 Abducens 7 Facial 8 Auditory 9 Glosso 10 Vagus 11 Spinal 12 Hypoglossal III.Identification.Provide the names of the following disorders of the nervous system on the blanks provided for. ______________________1. It describes a progressive and sometimes irreversible loss of intellectual functions that eventually impairs one’s ability to work and socialize. ______________________2. This is an infection of the meninges of the brain or of the spinal cord. [188] COURSE BOOK IN GENERAL BIOLOGY ______________________3. This is a disease that destroys myelin, the insulating substance of the nerve fibers which is important in having a normal electrical conduction in the nervous system. _____________________ 4. It is sometimes called “shaking palsy”, a movement disorder characterized by progressive tremor at rest, stiff limbs and trunk, slow movements, loss of facial expression and loss of postural control. _____________________ 5. It is not a specific disease but a group of symptoms involving the tendency to excessive electrical excitability of the brain. Manifestations of this include loss of consciousness, muscle spasms or involuntary motions causing seizures. ______________________6. This is a defect of the language center of the brain, believed to result from the failure of one cerebral hemisphere to respond to written language. ______________________7. This is a motor nerve disorder characterized by partial paralysis and lack of muscular coordination. This is caused by damage to the motor areas of the brain during pre-natal development, birth of infancy. ______________________8. This is a neurological disorder attributed to sudden interruption of the blood supply to a part of the brain. This may be caused by thrombus formation, embolus or hemorrhage. [189] COURSE BOOK IN GENERAL BIOLOGY ______________________9. This disease usually develops during the later years and is marked by gradual but inevitable deterioration of all mental processes. _____________________10. It is also called infantile paralysis and is caused by a virus that destroys nerve cell bodies within the anterior horn of the spinal cord. Fever, severe headaches, stiffness, pain and the loss of certain reflexes usually occur. [190] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.5 . Circulatory System Objectives: 1. to explain the functions of the circulatory system 2. to show variations in the circulatory system of animals 3. to discuss the human cardiovascular system and its components 4. to compare pulmonary and systemic circulation The circulatory system is an organ system that passes nutrients (such as amino acids, electrolytes and lymph), gases, hormones, blood cells, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH in order to maintain homeostasis. This system is composed of the cardiovascular system that distributes blood, and the lymphatic system, which distributes lymph. Humans, as well as other vertebrates, have a closed ciculatory system wherein the blood never leaves the network of arteries, veins and capillaries. Some invertebrate groups have an open circulatory system, wherein the blood is drawn back toward the heart through open-ended pores The most primitive animal phyla lack circulatory systems. The lymphatic system, on the other hand, is an open system. Human cardiovascular system The human cardiovascular system is composed of theheart, the veins, the arteries and the capillaries. [191] COURSE BOOK IN GENERAL BIOLOGY The heart (Figure 1) has one atrium and one ventricle for each circulation. With both a systemic and a pulmonary circulation, the heart is made up of four chambers: left atrium, left ventricle, right atrium and right ventricle. The right atrium is the upper chamber of the right side of the heart. The left atrium receives newly oxygenated blood from the lungs as well as the pulmonary vein which is passed into the strong left ventricle to be pumped through the aorta to the different organs of the body. The heart contracts and relaxes in rhythmic patterns. When it contracts, it pumps blood. When it relaxes, blood fills in. This cycle of pumping (systole) and filling (diastole) is called a cardiac cycle. Arteries carry blood away from the heart to organs throughout the body. Within organs, arteries branch into arterioles, small vessels that convey blood to capillaries. Capillaries are microscopic vessels that network into and infiltrate each tissue. Exchange of chemicals from the blood and the interstitial fluid around the tissue cells happen across the thin walls of capillaries. As the capillaries proceed towards their end, they converge into venules and venules converge into veins. Veins carry blood back to the heart. [192] COURSE BOOK IN GENERAL BIOLOGY Figure 1.The heart. View from the front, which means the right side of the heart is on the left of the diagram Blood flows within the vessels and consists of plasma, red blood cells, white blood cells, and platelets. An average adult contains five to six quarts (roughly 4.7 to 5.7 liters) of blood. Pulmonary circulation vs. Systemic Circulation Pulmonary circulation entails the transport of oxygen-depleted blood away from the heart to the lungs, and the return of oxygenated blood back to the heart. Oxygen-deprived blood from the superior and inferior vena cava enters the right atrium of the heart and flows through the tricuspid valve into the right ventricle, from which it is pumped through the pulmonary semi[193] COURSE BOOK IN GENERAL BIOLOGY lunar valve into the pulmonary arteries and from here, bloods flows to the lungs. Pulmonary veins return the oxygen-rich blood to the heart, where it enters the left atrium. Systemic circulation, on the other hand, transports oxygenated blood away from the heart to the rest of the body, and returns oxygen-depleted blood back to the heart. This type of cardiovascular circulation is, distancewise, much longer than pulmonary circulation, transporting blood to every part of the body including the heart. [194] COURSE BOOK IN GENERAL BIOLOGY Name: ______________________________ Score: ______________ Course: ____________________________ Date: _______________ Exercise No. 1 I.Fill in the table below to compare the circulatory system of different animals. Animal Circulatory Number of Single or Closed Group System heart double or Present or chambers circuit open Absent circuit Flat worms Annelids Cephalopods Fishes Amphibians Reptiles Birds Mammals II. TRUE OR FALSE. Write TRUE if the statement is correct and FALSE if it is incorrect on the spaces provided before each number. [195] COURSE BOOK IN GENERAL BIOLOGY ________1. Deoxygenated blood is exchanged with oxygenated blood in pulmonary circulation. ________2. Oxygenated blood is supplied throughout the body through systemic circulation. ________3. In systemic circulation, blood enters the lungs from the heart via the pulmonary veins. ________4. The blood from the different parts of the body enters the left atrium thru the vena cava. _______5. Arteries, except the pulmonary arteries, carry oxygen-rich blood away from the heart. _______6. Blood is confined to vessels and is distinct from interstitial fluid surrounding the organs in a closed circulatory system. _______7. Insects and other arthropods have an open circulatory system. _______8. Examination of the blood is necessary to understand the condition of the body. _______9. Valves in the heart prevent the backflow of blood and keep the blood from flowing toward the correct direction. ______10. By feeling your pulse rate, you can measure your heart rate. III. Differentiate the following terms from each other. 1. Arteries from veins in terms of structure and function. [196] COURSE BOOK IN GENERAL BIOLOGY 2. Red blood cells from white blood cells as to normal blood count and function. 3. Atrio-ventricular valve from semi-lunar valve as to location and function. 4. Pulmonary circulation fromsystemic circulation as to direction of blood flow. 5. Blood type AB from blood type O in terms of antigen and antibody component. [197] COURSE BOOK IN GENERAL BIOLOGY [198] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.6 : The Reproductive System Objectives: 1. to determine the parts and functions of the reproductive system 2. to differentiate asexual from sexual reproduction 3. to know the differences between the human female reproductive system and the male reproductive system. 4. to identify the stages of the menstrual cycle. The reproductive system or genital system is composed of organs which work together for the creation of new individuals from existing ones so that the species may continue to exist on earth. Most vertebrate animals have generally similar reproductive systems consisting of gonads, ducts, and openings. However, there is a great diversity of physical adaptations as well as reproductive strategies in every group of vertebrates. Most animals exhibit reproductive cycles which are often related to changing seasons. They reproduce only at certain times of the year and the best environmental condition will favor survival of the offspring. Asexual versus Sexual Reproduction Animal reproduction may be asexual or sexual. By asexual reproduction, new individuals are created with genes that came from one parent without the fusion of the egg and sperm. Many invertebrates reproduce asexually by fission, budding, and fragmentation. [199] COURSE BOOK IN GENERAL BIOLOGY Sexual reproduction on the other hand, is the creation of offspring by the fusion of haploid female gamete, (egg) and the male gamete (sperm) to form a zygote (fertilized egg) which is diploid. With sexual reproduction, the genetic variability among the offspring is increased with unique combinations of genes inherited from two parents. In sexual reproduction, the mechanism of fertilization is very important. Some animals have external fertilization (eggs are released by the female into a wet environment, where they are fertilized by the male. Other species, on the other hand, have internal fertilization (sperms are deposited in or near the female reproductive tract to meet the eggs). Human Reproductive System Humans reproduce by sexual reproduction. While both male and female are responsible for perpetuating the species, it is the female body that is responsible for nurturing the offspring from the time of conception to birth. The human female reproductive system is composed of: the female external reproductive structures which include the clitoris and two sets of labia, majora and minora, that surround the clitoris and vaginal opening; the internal organs which include the vagina, the receptacle for the male's sperm, the fallopian tube or oviduct which serves as the site of fertilization, the fimbriae of the fallopian tube which receives the released oocyte, the uterus, which holds the developing fetus, and the ovaries, which produce the female's ova. [200] COURSE BOOK IN GENERAL BIOLOGY The vagina is connected to the uterus through the cervix, while the uterus is connected to the ovaries via the fallopian tubes. At certain intervals, typically approximately every 28 days, the ovaries release an ovum (ovulation), which pass through the fallopian tube into the uterus. The lining of the uterus, called the endometrium, and unfertilized ova are shed each cycle through the process of menstruation. Female hormones are secreted in rhythmic fashion throughout the menstrual or estrous cycle (Figure 1) Figure 1.The Menstrual Cycle. Source:http://uhandbag.typepad.com [201] COURSE BOOK IN GENERAL BIOLOGY The human male reproductive system primarily functions to produce and provide the male gamete or spermatozoa for fertilization of the ovum. The major reproductive organs of the male can be grouped into three categories namely: sperm production (testes) and storage (epididymis), the ejaculatory fluid producing glands (seminal vesicles, prostate and the bulbourethral glands); and organs for copulation and deposition of the sperm, the penis, urethra, vas deferens and ejaculatory ducts. The testes are the primary male sex glands which are suspended from the abdominal region in a sax called the scrotum. It is primarily responsible for the manufacture of sperms and production of the male sex hormone, testosterone. The vas deferens leads from each testis to the seminal vesicles and from this point distally, it is considered as the ejaculatory duct. The seminal vesicles prostate glands and the bulbourethral glands secrete substances that go to form part of the semen which is the collective term which includes not only the sperms but also the secretions of the aforementioned glands. The epididymis serves as the storage area of sperms until they are ejaculated. The penis, an erectile tissue containing numerous blood vessels is the organ of copulation. Figure 2 shows the human female and male reproductive systems. [202] COURSE BOOK IN GENERAL BIOLOGY Figure 2. The human reproductive system. Female (left). Male (right) (Source: en.wikipedia.org) [203] COURSE BOOK IN GENERAL BIOLOGY [204] COURSE BOOK IN GENERAL BIOLOGY Name __________________________________ Score __________ Course & Year _________________________ Date ___________ Exercise No. 1 I.Choose the best answer and write your answer on the space provided for before each number. ____ 1. Which of these structures are mismatched? A. Testis and ovary C. fallopian tube B. vagina and penis D. seminal vesicle and prostate gland ____ 2. Which among these animals do not reproduce asexually? A. Sponges C. Coral B. Frog D. Sea star ____ 3. Which part of the male reproductive system does maturation and development of the sperm cells happen? A.Testis C. Epididymis B. Penis D. Vas deferens ____ 4. Egg cells are transported to the uterus through the A. Vagina C. Ovary B. Fallopian tubes D. Cervix ____ 5. Eggs are to ovary; sperms are to ___. A. Penis B. Epididymis C. Vas deferens D. Testis [205] COURSE BOOK IN GENERAL BIOLOGY ____ 6. The following are associated with asexual reproduction except A. Budding C. Fertilization B. Fragmentation D. Fission ____ 7. Which is not found in a female reproductive system? A. Ovary C. Vas deferens B. Clitoris D. Vagina ____ 8. Which is of the following is an accessory sex structure in males? A. Gonads C. Broad shoulders B. Gametes D. Seminal Vesicles ____ 9. When the ovaries are removed, which of the following will likely result? A. Pregnancy will occur. B. Menstruation will stop. C. The eggs will be produced in the fallopian tubes. D. The eggs will be fertilized in the womb. ____10. Which of the following describes menstruation? A. Rupture of the follicle and release of the egg B. Production of estrogen by the follicle C. Periodic loss of blood and tissue from the uterus D. Passage of egg into the fallopian tube. [206] COURSE BOOK IN GENERAL BIOLOGY ____11. Which of the following sequences of the menstrual cycle is correct? A. Follicle formation, corpus luteum, ovulation, menstruation B. Ovulation, menstruation, follicle formation, corpus luteum C. Follicle formation, ovulation, corpus luteum, menstruation D. Menstruation, follicle formation, corpus luteum, ovulation ____12. Ovulation usually occurs on the A.14th day after the last menstrual flow B. Just after the menstrual flow C. During menstrual flow D. Before menstrual flow ____13. The male gonads are called A. Sperm cells C. Ova B. ovaries D.testes ____14. When the egg is released from the ovary, which of the following happens? A. FSH and LH are at the peak of concentration B.The estrogen increases its secretion C.The uterus is very much prepared for the coming of its occupant D.All of the above ____15. Which of the following is true? A. The activities of the ovaries are influenced by FSH and LH [207] COURSE BOOK IN GENERAL BIOLOGY B. The activities of the uterus are influenced by estrogen and progesterone C. The pituitary gland has control over the ovaries and uterus. D. All of the above II. Essay. Answer the following questions briefly. 1. Discuss the advantages of having either few offspring ormany offspring as reproductive strategies in animals. 2. How does the menstrual cycle proceed? [208] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.7: The Respiratory System Objectives: 1. to identify the parts and functions of the respiratory system. 2. to compare the respiratory systems of different animals. 3. to discuss the processes involved in respiration The respiratory system primarily functions for gas exchange, the uptake of molecular oxygen (O2) from the external environment and the release of carbon dioxide (CO2) from an organism to the environment. Air, for terrestrial animals, and water for most aquatic animals, are the sources of oxygen for gas exchange. Each source is called the respiratory medium. Respiratory surface on the other hand, is the animal’s part where exchange of gases takes place. Presented below is the variation in respiratory surface of different animals. Name of Organism Respiratory surface 1. Protists Entire body surface 2. Sponges,cnidarians, Plasma membrane of every flatworms cell in the body 3. Earthworms Entire outer skin 4. Amphibians Entire outer skin and lungs 5. Fishes Gills as a respiratory organ [209] COURSE BOOK IN GENERAL BIOLOGY 6. Insects Tracheal system 7. Birds and mammals Lungs 8. Reptiles except turtles Lungs 9. Turtles Lungs and moist epithelial surfaces in mouth and anus Respiration in Man In humans, the organs of the respiratory system include airways or conducting pathways (nostrils or external nares, nasal choanae, pharynx, larynx, trachea, bronchi and their smaller branches), the lungs(for exchange of gases), and the respiratory muscles. The nostrils are paired external openings which open directly into the nasal choanae. The nasal choanae includes the external entrance which is guarded by hairs, a middle portion lined with pseudo-ciliated epithelium which contains mucous-secreting unicellular goblet cells, and a posterior portion containing receptors for the sense of smell. The pharynx is a short tube leading to the larynx and is a common passageway of food and air. The larynx has an opening called the glottis guarded by a valve-like epiglottis which prevents food and liquid from entering the larynx. It is also home to the vocal cords. The trachea continues from the larynx and bifurcates into two to form the two primary bronchi. The lungs, located in the pleural cavity, are the main organs of respiration in man and other animals. [210] COURSE BOOK IN GENERAL BIOLOGY Respiration consists of four events. These are as follows: 1. Breathing or pulmonary ventilation. This is the process of moving air into (inhalation) and out (exhalation) of the lungs as a result of volume and pressure change in the lungs. 2. External Respiration or pulmonary exchange. This is the loading of the oxygen gas from the alveoli to the blood and unloading of carbon dioxide from the blood to the alveoli. 3. Gas Transport. This the process wherein oxygen and carbon dioxide are transported to and from the tissue cells through the blood. Most of the oxygen attaches to the hemoglobin of the RBCs to form oxyhemoglobin while few are dissolved in the plasma for transport. 4. Internal Respiration. This is the exchange of oxygen and carbon dioxide between the blood and tissues cells. Here, oxygen is released from hemoglobin and diffuses out of the blood to enter tissues cells. Carbon dioxide, on the other hand, diffuses out of tissue cells into interstitial tissue fluid and into the blood. The oxygen supplied in the tissues is important to support the production of ATP in cellular respiration. [211] COURSE BOOK IN GENERAL BIOLOGY [212] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________ Score: ____________ Course: _________________________ Date: ____________ Exercise No. 1 I. Multiple Choice. Choose the best answer. Write the letter of your choice on the space provided before each number. ____ 1. In the respiratory system, the transport of oxygen in the blood from the lungs is called A. Internal respiration C. External respiration B. Cellular respiration D.Pulmonary ventilation ____ 2. Which of the following is true regarding respiration? A. Respiration is influenced by centers located in the medulla oblongata. B. At the end of respiration, the pressure in the alveolar space within the lungs is atmospheric. C. At the end of respiration, the pressure in the alveolar space is sub-atmospheric. D. Respiration is influenced by centers in the cerebellum. ____ 3. Which of the following does not belong to the group? A. Larynx C. Nose B. Pharynx D. lungs [213] COURSE BOOK IN GENERAL BIOLOGY ____ 4. Which is a defense mechanism of the respiratory system? A.Hiccups C. Crying B. Sneezing D. yawning ____ 5. At the end of a normal inhalation, which is not accomplished? A. Chest is expanded C. Rib cage is elevated B. Chest is depressed D. Diaphragm is depressed ____6.Conducting zone structures of the respiratory system are respiratory passages. Which among the structures are not conducting zones? A. Alveoli C. Bronchi B. trachea D.Nostrils ____ 7. When one exhales, air flows through respiratory structures in what sequence? A. Alveolus, bronchiole, bronchus, larynx, trachea, pharynx, nasal cavity B. Alveolus, trachea, bronchus, bronchiole, larynx, pharynx, nasal cavity C. Alveolus, bronchus, bronchiole, trachea, larynx, pharynx, nasal cavity D. Alveolus, bronchiole, bronchus, trachea, larynx, pharynx, nasal cavity ____ 8. During inhalation, intrapulmonary pressure is A. greater than the atmospheric pressure [214] COURSE BOOK IN GENERAL BIOLOGY B. greater than intrapleural pressure C. less than the atmospheric pressure D. less than the intrapleural pressure ____ 9. Among the following factors, which affects the rate of breathing? A. Increased CO2 level C. both a & b B. Decreased pH level D. neither a nor b ____10. When air leaves the lungs and proceeds to the environment, the process is called A. internal respiration C. inhalation B. external respiration D. exhalation II. Essay: Answer the questions as required. 1. Breathing ventilates the lungs. Trace how breathing takes place in different animals. You may use a diagram to answer this. A.Insects D. Birds B.Fishes E.Humans C.Amphibians [215] COURSE BOOK IN GENERAL BIOLOGY [216] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.8. Endocrine System Objectives: 1. to identify the functions and the components of the endocrine system 2. to differentiate endocrine glands from exocrine glands 3. to differentiate hormone from target organs 4. to identify the hormones and the action of each in the human body 5. to classify hormones in terms of quality or kind Hormones and Target Cells The endocrine system is composed of glands and organs that release chemical messengers called hormones, directly into the blood to maintain homeostasis. Hormones act on target cells that may be anywhere in the body. Target cells have receptors that are specific to the signaling molecules. The binding of hormones to the receptors on or within the target cells influences the activity of the target cell or organ – that is, by decreasing or increasing the rate of a normal metabolic process. The following are the major processes controlled by hormones: 1. reproduction 2. growth and development 3. mobilizing body defenses against stressors 4. maintaining electrolyte, water, and nutrient balance of the blood 5. regulating cellular metabolism and energy balance [217] COURSE BOOK IN GENERAL BIOLOGY Hormone secretion is regulated by negative feedback mechanism— that is, when an internal and external stimulus trigger the release of a hormone, rising levels inhibit its further release. Thus, blood levels of many hormones vary only within a very narrow range. There are two kinds of hormones, namely: 1. Peptide Hormones or acid-based molecules. Theseare composed of amino acids. A peptide hormone binds to a cell-surface receptor. It does not enter the cell. 2. Steroid Hormones are made from cholesterol. This includes the sex hormones and those produced by the adrenal glands. Steroid hormones enter the cell and bind to receptors in the cytoplasm.They act more slowly than peptide hormones because of the time required to produce new proteins as opposed to activating proteins that are already present. The Major Endocrine Organs The major endocrine organs are presented in Figure 1 with the secretions and the action of their secretions shown in Table 1. [218] COURSE BOOK IN GENERAL BIOLOGY Figure 1 The Major Endocrine Organs A. thyroid B. pituitary gland C. pineal gland D. thymus E. adrenal glands F. pancreas G. ovaries (female) H. testes (male) (Source: http://images.yourdictionary.com ) [219] COURSE BOOK IN GENERAL BIOLOGY Glands A. Thyroid Hormones Thyroxine Action Increases metabolic rate B. Pituitary anterior lobe ACTH(adenocortico Stimulates adrenal trophic hormone cortex to secrete glucocorticoids TSH( thyroid stimulating hormone) Energizes the thyroid gland to produce thyroxine FSH(follicle stimulating hormone) Growth Hormone Stimulates production of ova and sperm LH(luteinizing hormone Causes the increase in size of all tissues Prolactin Stimulates ovaries and testes ADH (Antidiuretic posterior lobe Hormone) Stimulates Oxytocin [220] production milk and COURSE BOOK IN GENERAL BIOLOGY secretion Promotes resorption of water in kidney tubules Causes contraction of uterus C. Pineal Melatonin Involved in the formation of biological rhythms D. Thymus Thymosin Acts as an incubator for the maturation of Tcells E. Adrenal Glucocorticoids adrenal cortex Mineralocorticoids Raise glucose level in the blood Promotes resorption of Na+ Epinephrine and and excretion of norepinephrine K+ in kidneys adrenal medulla Raise blood glucose level in the blood; [221] increase COURSE BOOK IN GENERAL BIOLOGY metabolic activity; constrict certain blood vessels F. Pancreas Insulin Lowers blood glucose level Glucagon Raises blood glucose level G. Ovaries Estrogens Stimulate lining uterine growth; promote Progesterone development and maintenance of female secondary sex characteristics. Promotes uterine lining growth H. Testes Androgens Support sperm formation; promote development and maintenance of male sex characteristics. Table 1: Major Endocrine Glands and Some of their Hormones [222] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________ Score: ____________ Course: _________________________ Date: _____________ Exercise No. 1 A. Multiple choice: Choose the best answer by writing the letter of your answer on the space provided before each number. ____ 1. Obligatory resorption of water in the kidney occurs because of a. ACTH b. ADH c. TSH d. LH ____ 2. In the non-pregnant female, the principal site of estrogen production is a. fallopian tube b. uterus c. cervix d. ovary ____3. Which of the following is not an exocrine gland? a. sweat gland b. pancreas c. pineal d. thymus ____ 4. Insulin and glucagon released by the pancreas reach their target cells because of the a. blood b. lymph c. pancreatic duct cystic ducts ____ 5. Abnormally low concentrations of estrogen result in a. very late appearance of pubic hair b. Increased deposition of fat in the subcutaneous c. Increased retention of sodium and water d. Decreased height. [223] d. COURSE BOOK IN GENERAL BIOLOGY ____ 6. In mammals, prolactin stimulates the production of milk. What structure is responsible for this? a. Adrenal gland b. pituitary gland c. ovaries d. pineal gland ____ 7. The pancreas is both an endocrine and an exocrine gland because a. It secretes both serous and mucous enzymes. b. It secretes hormones and enzymes. c. It secretes enzymes only. d. It secretes hormones only. ____ 8. The submaxillary gland releases its secretions into the mouth via its ducts. This qualifies it to be called an a. Endocrine gland c. Both endocrine and exocrine b. Exocrine gland d. Neither endocrine nor exocrine ____ 9. Which of the following is/are the target organ/s of oxytocin? a. Ovary b. uterus c. testes pituitary gland ____10. All hormones of the adrenal cortex are synthesized from a. tyrosine b. glycoproteins [224] c. cholesterol d. fats d. COURSE BOOK IN GENERAL BIOLOGY B. Complete the table below. A. Supply the target organ/s for every hormone given below. Hormone Target organ/s, tissues or cells 1. Insulin 2. ADH 3. Epinephrine 4. Calcitonin 5. Estrogen B. Classify the hormone as to kind. Hormone Kind( steroid or peptide) 1. Androgen 2. Glucocorticoids 3. Thymosine 4. Glucagon 5. Thyroxine [225] COURSE BOOK IN GENERAL BIOLOGY [226] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.9. Excretory System Objectives: 1. to identify the parts of the excretory system 2. to give the importance of the excretory system 3. to differentiate the excretory system among animal groups 4. to discuss the excretory process in man Function of the Excretory System The excretory system is the organ system that gets rid of nitrogencontaining waste products of metabolism which may be in the form of ammonia, urea, or uric acid. The excretory system is built on a complex network of tubules that provides a large area for the exchange of water and solutes including nitrogenous wastes. The excretory system works with the lungs, skin, and intestines -all of which also excrete wastes- to keep the chemicals and water in the body balanced. Excretory System of Different Animals The excretory system varies widely among animal groups. The following are the variations: [227] COURSE BOOK IN GENERAL BIOLOGY 1. Flatworms - have protonephridia, a network of dead-end tubes that lack internal openings. 2. Earthworms and other annelids- have metanephridia, internal openings that collect body fluids. 3. Insects and other terrestrial arthropods - have Malpighian tubules that open into the digestive tract and dead-end at tips that are immersed in the circulatory fluid or hemolymph. 4. Vertebrates have kidneys which are built of tubules arranged in a highly organized manner. A dense network of capillaries is intimately associated with the tubules and ducts which carry urine out of the body. Excretion in Man The human excretory system includes two kidneys, two ureters, the bladder, the urethra, and the penis in males. [228] COURSE BOOK IN GENERAL BIOLOGY Figure 1. Human Urinary Sytem . Source: http//en.wikipedia.org 1. Human urinary system: 2. Kidney, 3. Renal pelvis, 4. Ureter, 5. Urinary bladder, 6. Urethra. (Left side with frontal section), 7.Adrenal gland Vessels: 8. Renalartery and vein, 9. Inferior vena cava, 10. Abdominal aorta, 11.Common iliac artery and vein 12.Liver, 13.Large intestine, 14.Pelvis The kidneys are the principal excretory organs of the body with the nephrons as their functional unit of structure. They excrete most of the urea and excess water, sugar and salts as urine in a process involving the following steps: [229] COURSE BOOK IN GENERAL BIOLOGY 1. Glomerular Filtration. Blood containing wastes, gases, water and other solutes are brought to the kidneys via the renal artery. These materials enter the glomerular capsule and pass through the proximal convoluted tubule and down the descending loop of Henle. 2. Reabsorption. As the fluids or materials pass down the descending Loop of Henle, those materials needed by the body are reabsorbed by the capillaries. It is a selective reabsorption for many of the materials. The substances reabsorbed are water and solutes, notable some NaCl, hormones, needed pigments, small amounts of nitrogenous wastes and all glucose. 3. Secretion. At the same time that tubular reabsorption is taking place, tubular secretion also occurs. The reabsorbed materials go to the capillaries and are brought back to the circulation via the renal veins. The remaining portion of the filtrate (those not reabsorbed) are voided out as urine. The nephron is the unit of structure and function of the excretory system. It contains the glomerulus where the waste products leave the circulatory system and are collected in the glomerular capsule or Bowman’s capsule. [230] COURSE BOOK IN GENERAL BIOLOGY The pathway of urine formation in the nephron, is shown in Fig.2. Figure 2. The Nephron Source:http://images.google.com. Humans produce about 2.9 liters of urine over 24 hours, although this amount may vary according to circumstances such as the amount of blood flow through the kidney, changes in body fluid status (amounts of fluid and food a person consumes and how much fluid is lost through sweat and breathing), and application of some medications that interfere directly or indirectly with urine production. Diuretics alter the amount of absorbed or excreted electrolytes or osmalites, which causes a diuresis.Problems in the urinary system can be caused by aging, illness, or injury. [231] COURSE BOOK IN GENERAL BIOLOGY [232] COURSE BOOK IN GENERAL BIOLOGY Name: __________________________ Score: ____________ Course: ________________________ Date: ____________ Exercise No. 1 I. Identification. Supply what is asked for in the following questions. A. What particular step in urine formation (filtration, reabsorption, secretion and excretion) is observed in the following excretion functions: 1. Concentrating urine ____________________________________ 2. Removal of urea _____________________________________ 3. Regulating electrolytes ____________________________________ 4. Maintaining acid-base homeostasis ____________________________________ 5. Retention of blood cells____________________________________ 6. Removal of creatinine from blood____________________________________ [233] COURSE BOOK IN GENERAL BIOLOGY 7. Proteins returned in the blood ____________________________________ 8. Reclaiming of water and glucose____________________________________ 9. Getting rid of drugs in the body___________________________________ 10. Blood pH balance _________________________________ B . In what particular part of the nephrons do the following events of urine formation take place? 1. Proteins returned in the blood __________________________________ 2. Retention of blood cells__________________________________ 3. Release of creatine into the filtrate __________________________________ 4. Reclaiming of water and glucose__________________________________ 5. Reabsorption of glucose and amino acids__________________________________ [234] COURSE BOOK IN GENERAL BIOLOGY Exercise No. 2 Essay: Answer the following questions briefly. 1. What causes the variation in urine color and quality? 2. Why is there a need to reabsorb some substances which might have joined the filtrate ? 3. Why is urine examination a useful protocol in physical examination? [235] COURSE BOOK IN GENERAL BIOLOGY 4. Trace the pathway of urine from the kidneys. 5. What changes occur in the kidney and the urinary bladder as one starts growing older? [236] COURSE BOOK IN GENERAL BIOLOGY Lesson 2.10. Muscular System Objectives: 1. to identify the functions of the muscular system 2. to identify the modes of locomotion of animal groups 3. to classify muscles accordingly 4. to discuss the mechanism and control of muscle contraction Muscle Function Locomotion or movement is the essential function of the muscular system. This ability of muscles is because of their unique characteristic of shortening or ability to contract. Muscles also provide strength, balance, posture, and heat for the body to be kept warm. Animals move in a variety of ways. Most animal phyla include species that swim. On land and on the sea floors, animals crawl, walk, run, or hop. Active flight has evolved in only a few animal groups including some animals like the birds and the bats. In order for these animals to do all of these, energy expenditure is a must. Muscle types There are three distinct types of muscles: skeletal muscles, cardiac or heart muscles, and smooth (non-striated) muscles. The table below shows the characteristics of these different types of muscles. [237] COURSE BOOK IN GENERAL BIOLOGY Skeletal Location Cardiac Smooth Attached to Walls of the Mostly in bones heart walls of the visceral organs Cell shape and Type of nucleus Single, very Branching Single, long, cylindrical chains of cells fusiform multinucleate Uninucleate uninucleate Presence/absence with very of striations obvious with striations No striations striations Regulation of Voluntary; via Involuntary; Involuntary; contraction nervous sytem Nervous system Nervous controls controls system Hormones controls Slow Very slow Speed of Slow to fast Contraction Figure 1. Types of Muscles (Source: http://www.ncbi.nlm.nih.gov [238] COURSE BOOK IN GENERAL BIOLOGY Mechanism of Muscle Contraction Fine strands called myofibrils compose muscle fibers. Each myofibril is divided into small segments called sarcomeres which are the basic units of muscle contraction. A sarcomere contains actin and myosin filaments which interact through a sliding mechanism that is able to shorten the sarcomere. Contraction of the sarcomere depends on the arrival of action potentials from motor neurons. These action potentials cause the release of calcium ions from the sarcoplasmic reticulum (membranous chambers surrounding the myofibrils). The calcium ions act to clear the binding sites on the actin filaments. Once a binding site is cleared, a myosin head can attach to the adjacent actin filament. When this happens, the myosin head is said to be in an energized state with energy coming from adenosine triphosphate (ATP). This energy causes the myosin head to change in shape. The change results in a short power stroke, whereby the actin filament is made to slide past the myosin filament, toward the center of the sarcomere. Another ATP molecule is picked up by the de-energized myosin head as it detaches from the actin filament. This myosin head then becomes energized and starts reattaching at the next binding site in line. A series of power stokes is required by a single contraction of the sarcomere In order for a series of power strokes and for muscle contraction to take place, ATP is necessary as a source of energy. The calcium ions, on the other hand, are necessary for the clearing of the binding site where the power stroke occurs. [239] COURSE BOOK IN GENERAL BIOLOGY Figure 2. The Sliding Filament Model of Muscle Contraction(Source:http://www.google.com.ph) Control of muscle contraction Neuromuscular junctions are the focal points where a motor neuron attaches to a muscle. Acetylcholine, (the specific neurotransmitter for skeletal muscle contraction) is released from the axon terminal of the neuron and diffuses across the synaptic cleft and attaches to receptors of the muscle cell membrane. This will make the sarcolemma temporarily permeable to sodium ions (Na+), which rush into the muscle cell. This condition will create an electrical change in the sarcolemma generating an electrical current called an action potential. The action potential travels over the entire surface of the sarcolemma conducting an electrical impulse from one end of the cell to the other resulting to the contraction of the muscle. While the action potential is occurring, acetylcholine, which began the process, is broken down by enzymes present in the sarcolemma. This [240] COURSE BOOK IN GENERAL BIOLOGY prevents continued contraction of the muscle cell in the absence of additional nerve impulses. When the action potential ends, calcium ions are immediately reabsorbed into the sarcoplasmic reticulum storage areas, and the muscle cell relaxes and settles back to its original length. Muscle Movements and Names of Muscles The action of muscles is always to contract but muscles can extend only passively -that is, their ability to move parts of the body to opposite directions requires that the muscles be attached to the skeleton in antagonistic pairs, each member of the pair working against each other. Examples of these muscles are flexors and extensors, abductors and adductors, pronators and supinators. There are other muscles named according to their location, arrangement/direction of fibers, relative size, location of attachment points such as origin and insertion, number of origins, and shape. [241] COURSE BOOK IN GENERAL BIOLOGY [242] COURSE BOOK IN GENERAL BIOLOGY Name: _______________________________ Course & Year _____________________ Score: ____________ Date: ____________ Exercise No. 1 A. Multiple Choice: Choose the best answer among the options given and write the letter of your choice on the space provided before each number. ____ 1.The thumb that someone sticks out to get a hitch ride is _____ the thumb. a. extending b. abducting c. adducting d. pronating ____ 2. Which of the following muscles contract because they can be controlled by the will ? a. skeletal muscles b. cardiac muscles c. smooth muscles d. viscera ____3. Among the following muscles, which is named according to movement? a. rectus abdominis c. biceps femoris b. abductor magnus d. internal oblique ____4. Peristalsis is the wavelike movement of the intestines. What type of muscle performs this function? a. skeletal muscle c. smooth muscle b. cardiac muscle d. none of these [243] COURSE BOOK IN GENERAL BIOLOGY ____5. Which is not a name of a muscle based on location? a. pectoralis major c. biceps femoris b. rectus abdominis d. extensor digitorum longus ____6. Which of the following does not characterize a cardiac muscle? a. intercalated disk c. with striations b. spindle shape cell d. uni-nucleated ____ 7. In what way domuscles work with the skin for thermoregulation? a. Muscles are connected to bones. b. Muscles contract to generate body heat. c. Muscles give form to the body. d. Muscles support the body. ____ 8. Which of the following steps in muscle contraction comes first? a. Calcium is released from the sarcoplasmic reticulum. b. Sodium ions rush into the cell. c. Acetylcholine diffuses into the synaptic cleft towards the muscle cell. d. Acetylcholine is broken down by the acetylcholinesterase. ____9. Which muscle name indicates its size? a. abductor magnus b. longissumus c. gluteus medius d. soleus ____10. What is not true about acetylcholine neurotransmitter? a. It is a hormone. [244] enzyme COURSE BOOK IN GENERAL BIOLOGY b. It generates action potential. c. It is found between a muscle and a nerve. d. It is hydrolyzed by an enzyme to stop functioning. B. Essay. Discuss the following briefly. 1. Diverse adaptations for traveling on land have evolved in various vertebrates. Using a diagram, show these adaptations in mammals. 2. Why is there a need for athletes to warm up before their game? 3. How do muscles contract? [245] COURSE BOOK IN GENERAL BIOLOGY [246] COURSE BOOK IN GENERAL BIOLOGY Chapter 7 Plant Reproduction and Development [247] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. Reproduction and Reproductive Cycles Objectives: 1. to describe sexual and asexual reproductive mechanisms in plants 2. to discuss the reproductive cycles in plants Asexual and Sexual Reproduction in Plants Reproduction is the process by which plantsgenerate new offspring. Plants have the potential to reproduce sexually and asexually. In plants, sexual reproduction means the formation of offspring by the fusion of gametes. In lower forms of plants, this involves the alternation of gametophyte and sporophyte generations that contain haploid and diploid cells respectively.In flowering plants, the diploid individual (sporophyte) is the main body and the haploid individuals (male and female gametophytes) are parts of a flower. Sexual reproduction results in offspring which are genetically different from the parents. Asexual reproduction is the formation of offspring without the fusion of gametes. Offspring are genetically identical to the parents except when mutation takes place. This type of reproduction in plants occurs either by vegetative reproduction or apomixis. [248] COURSE BOOK IN GENERAL BIOLOGY Female Gametophyte Male Gametophyte Meiosis Meiosis Sperm (n) Egg (n) Fusion (2n) Mitosis Sporophyte The Basic Plant Reproductive Cycle A generalized plant reproductive cycle (Taggart, 2007) has both haploid and diploid phases, connected by meiosis and fusion, but in all other aspects, there are some fundamental differences with respect to animals. [249] COURSE BOOK IN GENERAL BIOLOGY Specific cells in the mature diploid phase of the plant life cycle undergo meiosis, but this does not produce gametes. Instead, the haploid cells are known as spores. Since the diploid phase of the life cycle produces spores, it is known as the sporophyte phase of the plant life cycle. Spores typically develop into multicellular, haploid gametophytes. It is in the multicellular gametophyte stage that produces the gametes. Since the gametophytes are already haploid, the gametes are produced by mitosis, not meiosis. Thus, gametogenesis in plants is mitotic, not meiotic. [250] COURSE BOOK IN GENERAL BIOLOGY Name __________________________ Score___________ Course & Year ___________________ Date __________ Exercise No. 1 Multiple Choice.Select from the choices, the answer that best completes the statement and write the letterof your answeron the space provided before each number. _____ 1. Many plants have the capacity to reproduce a. sexually b. asexually c. by apomixis d. both sexually and asexually _____ 2. The plant part with haploid cells is called a a. sporophyte b. gametophyte c. megasporocyte d. microsporocyte _____ 3. A sperm and egg unite to form a diploid cell that develops into a a. sporophyte b. gametophyte c. megasporocyte d. microsporocyte [251] COURSE BOOK IN GENERAL BIOLOGY _____ 4. The part of the strawberry plant where vegetative reproduction occurs is the a. leaf b. root c. branch of a stem aboveground d. branch of a stem underground _____ 5. In vegetative reproduction, it is possible to a. culture a small piece of tissue taken from the stem and grow entire new plants b. produce new potato plants by using tissue culture c. graft stems or buds of one plant onto a different set of stems d. undergo A to C. ______ 6. The sporophyte generation in moss produces spores by a. meiosis b. mitosis c. sexual reproduction d. asexual reproduction ______ 7. The offspring produced through apomixis is a.genetically identical to its parent b. geneticallydifferent from its parent c. physically identical to its parent d. physically different from its parent [252] COURSE BOOK IN GENERAL BIOLOGY ______8. In many grasses, root formation takes place through a type of vegetative structure known as a. corm b. stolon c. sucker d. rhizome ______9. A severed part of a plant when placed in a favorable environment a. can grow into a new individual. b. grows a new (stem and) root. c. grows a new stem through a part of a root. d. can undergo letters A-C. ______ 10. Plant reproductive cycle characteristics entail a. male gametophyte producing sperms b. female gametophyte producing eggs c. sperm and egg uniting to form a diploid cell d. all of the above [253] COURSE BOOK IN GENERAL BIOLOGY [254] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Sexual Reproduction and Development in Higher Plants Objectives: 1. to distinguish between megasporogenesis and microsporogenesis 2. to explain the mechanics of pollination and fertilization 3. to describe the early development of a plant embryo 4. to describe the basic anatomy and development of fruits and seeds 5. to discuss various ways by which seeds and fruits can be dispersed in nature 6. to describe the process of seed germination Megasporogenesis and Microsporogenesis Megasporogenesis is the formation of megaspores inside the ovules of seed plants. In the ovules of angiosperms, megasporogenesis takes place within a structure called a nucellus. A diploid cell in the ovule, called a megasporocyte or megaspore mother cell, undergoes meiosis and gives rise to four haploid megaspores. In most plants, only one of the megaspores develops into a megagametophyte within the ovule, while the other three disintegrate. Microsporogenesis is the formation of microspores inside the microsporangia (or pollen sacs) of seed plants. A diploid cell in the microsporangium, called a microsporocyte or a microspore mother cell, undergoes meiosis and gives rise to four haploid microspores or pollen [255] COURSE BOOK IN GENERAL BIOLOGY grains (when ecapsulated). Each microspore divides mitotically producing two nuclei: the tube nucleus and the generative nucleus. The generative nucleus further divides mitotically, producing two sperm nuclei. Fertilization takes place when a pollen grain from the anther upon landing on the stigma of a pistillate flower elongates (called pollen tube at this time) until it reaches the ovary through the micropyle where double fertilization takes place. One sperm nucleus unites with the egg nucleus to form a diploid zygote which eventually becomes the embryo. The other sperm nucleus fuses with the polar nuclei to form the triploid endosperm. Fertilization allows the flower to develop seeds. Pollination Pollination is the transfer of pollen from the anthers of a flower to the stigma of the same flower or of another flower. Pollen grains contain the male gametes while the female gamete(s) are contained within the carpel. Pollination varies in gymnosperms and in angiosperms. Pollination is a prerequisite for fertilization and is a necessary step in the reproduction of flowering plants resulting in the production of genetically diverse offspring. Embryonic Development Plantembryogenesis is the process that produces an embryo from a fertilized ovule by asymmetric cell division and the differentiation of undifferentiated cells into tissues and organs. A similar process continues during plantgrowth within the meristems. [256] COURSE BOOK IN GENERAL BIOLOGY Embryogenesis occurs naturally as a result of sexual fertilization and the formation of the zygotic embryos. The embryo along with other cells from the mother plant develops into the seed or the next generation, which, after germination, grows into a new plant. Seed and Fruit Development Seed A seed develops after fertilization of an egg (found in a plant ovule) by a sperm (found in the pollen grain). When another sperm nucleus fertilizes the cell with two polar nuclei, the triploid cell formed divides by mitosis. Once the fertilized egg is completely surrounded with endosperm, it begins to develop an embryo. It first divides into two cells: a suspensor cell and an embryo cell. The suspensor cell then divides repeatedly to form a column of cells that connects the developing embryo to the inner wall of the ovule. The suspensor anchors the embryo and transfers nutrients into it from the endosperm. In gymnosperms, a hard and tough seed coat or testa protects the seed while a second membranous seed coat known as tegmen is present within the testa of angiosperms. Three embryonic tissues form when embryonic cells divide: radicle or embryonic root, embryonic bud or epicotyl/plumule, and embryonic stem or hypocotyl that connects the radicle to the cotyledon or seed leaf. The [257] COURSE BOOK IN GENERAL BIOLOGY number of cotyledons present can be used to classify angiosperms as monocot or dicot. Fruit While the ovule is developing into a seed, the ovary around it is developing into a fruit. A fruit is a structure of a plant that contains its seeds. Fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state. In biology, a "fruit" is a part of a flowering plant that derives from specific tissues of the flower, mainly one or more ovaries. Though fruits vary in appearance, they have the same basic three layers; the outermost exocarp, middle mesocarp and innermost endocarp. Different types of plants develop fruits that can be fleshy like mangoes, or dry such as rice. Some common vegetables like tomatoes, eggplants, string beans and squash are considered as fruits since these are developed from ovaries. Seed and Fruit Dispersal The primary function of a fruit is dispersal – movement of the seed (and embryo) to new areas away from the parent. For example, fruits of the narra tree and cogon grass are aerodynamic and drift with the wind; the pods of peas and beans split open and eject their seeds. Coconuts float on water. Guavas, cherries and raspberries are eaten by animals; the fruits are digested but the seeds pass through the digestive tract and are deposited in feces some distance from the parent plant. [258] COURSE BOOK IN GENERAL BIOLOGY Seed Germination Germination is the process of a seed breaking dormancy, the embryo becoming a seedling, and eventually a developed plant. Germination is the activation of a dormant embryo under favorable environmental conditions. It begins with absorption of water, which swells the seed and ruptures the seed coat. Cells of the embryo then begin to divide and enlarge. The first structure to emerge from the seed is a root, and when this happens, the embryo contacts its environment and becomes a seedling. A stem soon grows upward through the soil and leaves appear. [259] COURSE BOOK IN GENERAL BIOLOGY [260] COURSE BOOK IN GENERAL BIOLOGY Name __________________________ Score ___________ Course & Year ___________________ Date __________ Exercise No. 1 Multiple Choice. Select from the choices the answer that best completes the statement and write the letter of your answeron the space provided before each number. _____ 1. In the life cycle of angiosperms, a microspore develops into a/an A. female gametophyte B. male gametophyte C. megaspore D. embryo E. ovule _____ 2. After an egg has been fertilized, a fruit develops from the A. nuclei B. ovary C. ovule D. sepal E. carpel ______ 2. In the following choices involving the development of the embryo, the mismatched combination is A. cotyledon – seed leaf. B. epicotyl – root. C. plumule – leaves. [261] COURSE BOOK IN GENERAL BIOLOGY D. carpel – ovule. E. pericarp – kernel ______3.The following are embryonic tissues except A. hypocotyl B. radical C. plumule D.cotelydon E. epicotyl _____ 4. To a plant, the primary purpose of the fruit is A. to provide nutrition for the seed. B. to allow cross-fertilization. C. for photosynthesis D. to disperse seeds. E. all of the above ______ 5. A typical seed contains all of the following except A. zygosporangium B. cotyledon C. seed coat D. embryo E. radical ______ 6. In gymnosperms, the process of transferring pollen from a male cone to a female cone is called A. alternation of generations. B. asexual reproduction. [262] COURSE BOOK IN GENERAL BIOLOGY C. seed fermentation. D. pollination E. apomixis. ______ 7. The cotyledons in a seed A. develop into flowers. B. are vestigial structures. C. develop from the seed coat. D. provide a source of food for the embryo. E. all of the above. ______ 8. Plants that produce seeds enclosed in fruits A. are gymnosperms. B. have flowers. C. produce male and female cones. D. also produce spores. E. all of the above. _____ 9. Higher plants have a polar main axis with definite stem and root ends. This polarity is first established A. at the time the plant is old enough to produce leaves B. just before the flower forms on the parent plant C. when the seedling first grows into the light D. when germination first starts in the soil E. in the embryo of the seed _____ 10. Evolutionary change in both a pollinator and a flower resulting from their interaction is an example of [263] COURSE BOOK IN GENERAL BIOLOGY A. convergent evolution B. regressive evolution C. divergent evolution D. parallel evolution E. co-evolution _____ 11.What does a seed contain which provides energy for germination? A. soil B. water C. sunlight D. stored food E. endosperm _____ 12. The main purpose of a plant’s flowers is to A. produce food B. provide water C. produce seeds D. provide support E. produce new offspring _____ 13.Cone bearing plants are those considered as A. gymnosperms B. angiosperms. C. those whose seeds are not enclosed by fruit. D. flowers for reproductive success. E. plants that depend on an aqueous environment for gamete dispersion. [264] COURSE BOOK IN GENERAL BIOLOGY _____ 14. The cotyledons of angiosperms A. enclose the flower bud B. store food in the seed C. become the spore D. become the fruit E. form pollen _____ 15. Angiosperms differ from other terrestrial plant groups in that They have flowers and fruits. B. They have cones. C. They have needles. D. They produce spores. E. All of the above. _____ 16. The seeds stockpile nutrients such as starches, sugars, amino acids, proteins and oils in the A. germ B. embryo C. coleoptile D. endosperm E. None of the above ____ 17. What substance inhibits leaf abscission and promotes bud and seed dormancy? A. abscisic acid B. gibberellins C. cytokinins D. ethylene [265] A. COURSE BOOK IN GENERAL BIOLOGY E. auxins ____ 18. Which substance promotes plant growth and phototropism? A. abscisic acid B. gibberellins C. cytokinins D. ethylene E. auxins _____ 19. What produces fruit color change and cause fruits to ripen by stimulating the conversion of starch into sugar? A. phytochrome B. gibberellin C. ethylene D. cytokinin E. auxin _____ 20. Flower bearing plants are known as A. gymnosperms B. angiosperms C. complete plants D. both A and B D. none of the above [266] COURSE BOOK IN GENERAL BIOLOGY Name ____________________________ Score___________ Course & Year ___________________ Date __________ Exercise No. 2. Identification: Identify the structures on the flower (Fig. 1) and seed (Fig. 2). Figure 1. Flower Structure Figure. 2. Seed Structure [267] COURSE BOOK IN GENERAL BIOLOGY [268] COURSE BOOK IN GENERAL BIOLOGY Name ___________________________ Score__________ Course & Year ____________________ Date _________ Exercise No. 3 Fill-in the blanks: Place your answer on the spaces provided for. 1.The embryo of a flowering plant develops inside an _______________. 2. An _______________ is a structure consisting of an egg inside protective cells, that develops into a seed. 3. The male, or pollen-producing part of a flower is called the ________________. 4. The narrow, midsection of the pistil which contains the pollen tube is the _______________. 5. The entire female reproductive organ in flowering plants is called the _____________. 6. The transfer of pollen between the anther and the stigma in any flowering plant or plants is called _______________. 7. Most stored food in a bean seed is contained in its ________________. [269] COURSE BOOK IN GENERAL BIOLOGY 8. A _______________ is a thickened ovary, specialized as a vessel that encloses and protects the seeds and facilitates dissemination. 9. The embryonic plant is called a _______________ before germination. 10. A _______________ is an embryonic leaf that absorbs nutrients from the endosperm and transfers them to the rest of the embryo. [270] COURSE BOOK IN GENERAL BIOLOGY Chapter 8 GENETICS [271] COURSE BOOK IN GENERAL BIOLOGY [272] COURSE BOOK IN GENERAL BIOLOGY Lesson 1. Genetics: Heredity and Variation Objectives: 1. to differentiate the types of variations among organisms 2. to explain the laws of heredity and their applications to inheritance Genetics is the study of heredity and variation. It deals with how physical, biochemical, behavioral and sexual traits are transmitted from parents to offspring. The transmission of these traits is due to heredity and the information passed is encoded within molecules of DNA. Variations are likewise basic qualities of life. They refer to distinct differences among organisms and provide the raw materials for adaptation and evolution. The science of genetics began when an Austrian monk, Gregor Mendel, discovered that hereditary characteristics were determined by genes transmitted from one generation to the next. His important contribution to genetics was his being able to demonstrate that the appearance of different inherited characters followed specific laws which were determined by the diverse kinds of offspring produced from sets of crosses. From his work, two important attributes of the gene have been determined: (1) The gene is inherited from generation to generation in such a way that each progeny has a physical copy of this material. [273] COURSE BOOK IN GENERAL BIOLOGY (2) The gene provides the information as to the structure, function and other biological attributes of an individual. [274] COURSE BOOK IN GENERAL BIOLOGY Name _____________________________ Score ___________ Course & Year _____________________ Date ___________ Exercise No. 1 A. Complete the Table. Supply the specific type of variation vis-a-vis the following traits enumerated in the first column. Place your answer in the corresponding space on the second column. Trait Type of Variation 1. Color blindness 2. Tongue rolling 3. Ability of plants to photosynthesize 4. Milk production 5. Elaborate and colourful feathers 6. Leaf shape 7. Mental retardation 8. Astigmatism 9. Shape of ear lobes 10.Inability to absorb glucose B. Essay: Differentiate the following fields of Genetics from each other. [275] COURSE BOOK IN GENERAL BIOLOGY a. Cytogenetics _____________________________________________________ _____________________________________________________ _____________________________________________________ ______________________ b. Molecular Genetics _____________________________________________________ _____________________________________________________ _____________________________________________________ __________________ c. Population Genetics _____________________________________________________ _____________________________________________________ _____________________________________________________ __________________ [276] COURSE BOOK IN GENERAL BIOLOGY Lesson 2. Methods and Applications of Genetic Study Objectives: 1. to identify the different methodsof genetic study 2. to enumerate the applications of genetics in several aspects of life The discovery of tools that have enabled geneticists to study more aspects of genetics have been observed from the past years. Different methods have been developed and studied that have allowed the detailed investigation and characterization of genes and chromosomes in plant and animal species. These are: Plant Breeding Experiments, Pedigree Analysis, Statistical Analysis, Twin Studies, Karyotyping, Microbial and Molecular Genetics, Population Genetics, and Computer Studies. These methods have likewise allowed certain correlations of phenotypic traits to certain chromosomal aberrations and have provided the chromosomal basis of sex determination. Genetics has several applications. Examples of such are: improvements in food crops and domestic animals by selective breeding, and identification of the genetic bases of diseases and abnormalities. Genetics can now also be applied in the repair of genes that produce defective traits and can be used in solving certain legal problems. [277] COURSE BOOK IN GENERAL BIOLOGY [278] COURSE BOOK IN GENERAL BIOLOGY Name _____________________________ Score _________ Course and year __________________ Date __________ Exercise No. 2 A. Identification:Identify the appropriate method of genetic study to be used in the following cases. __________________ 1. Use of breeding organisms exhibiting contrasting expressions of the same trait __________________ 2. Use of existing marriages or analysis of family trees to gather pertinent hereditary information __________________ 3. Use of special statistical test to measure the degrees of concordance or discordance in identical or fraternal twins __________________4. Involves getting a pictorial representation of the chromosomes of an organism __________________ 5. Makes use of serological techniques, electron microscopy or radioisotope labeling to facilitate the investigation of the nature and mode of action of the genetic material B.Enumeration: Give examples of practical applications of genetic principles in a. Plant and animal improvement _______________________________________________ _______________________________________________ [279] COURSE BOOK IN GENERAL BIOLOGY _______________________________________________ b. Human genetics _______________________________________________ _______________________________________________ _______________________________________________ c. Medical field _______________________________________________ _______________________________________________ _______________________________________________ _______________________________________________ [280] COURSE BOOK IN GENERAL BIOLOGY Lesson 3. The Chromosomal Basis of Heredity Objectives: 1. to point out the consequences of mitosis and meiosis in the transmission of hereditary traits in different organisms 2. to discuss the genetic significance of the random separation of chromosome pairs in resulting gametes The cell consists of two regions: the cytoplasm, and the nucleus. Prokaryotic cells like bacteria and blue-green algae have no nuclear membrane while in eukaryotes, a nuclear membrane separates the genetic material from the surrounding cytoplasm. The nucleus primarily directs cellular activity and inheritance as it contains the chromatin/chromosomes. These chromosomes bear the hereditary materials or the genes. Through cellular division, the mechanisms of genetic transmission can be explained. In mitosis, the genetic and chromosome composition of a cell is faithfully reproduced in each of the daughter cells. Meiosis, however, results in chromosome number of cells which is reduced to half its usual number. In this case, this reduction results to the ultimate production of male and female gametes which, when fused during fertilization, restores the chromosome number of the species. [281] COURSE BOOK IN GENERAL BIOLOGY [282] COURSE BOOK IN GENERAL BIOLOGY Name _________________________ Score ___________ Course and year _______________ Date ___________ Exercise No. 3 A. Arrange the following events according to their occurrence during meiosis. Write the letter of the events on the space provided after the number below. a. Crossing-over between homologues and the consequent formation of chiasma b. Condensation of chromosomes and their independent alignment along the equatorial plate c. Alignment of the paired chromosomes along the equatorial plate d. Complete separation and movement of the univalents (dyads) of each bivalent to the opposite poles e. Splitting of the centromeres f. Reconstitution of the nuclear envelope and the consequent formation of four haploid cells g. Formation of two haploid daughter cells h. Pairing of homologous chromosomes i. Chromosomes recognized as long, thin filaments and the consequent disintegration of the nuclear membrane j. Longitudinal separation of the bivalents with the synaptonemal complex no longer functional [283] COURSE BOOK IN GENERAL BIOLOGY 1. _________ 6. _________ 2. _________ 7. _________ 3. _________ 8. _________ 4. _________ 9. _________ 5. _________ 10.________ B. Make diagrams of cells undergoing the following stages of mitosis or meiosis, as indicated, wherein the diploid chromosomal number of the cell is equal to two. a. Metaphase b. Metaphase I c. Metaphase II d. Anaphase e. Anaphase I f. Anaphase II [284] COURSE BOOK IN GENERAL BIOLOGY Lesson 4. Mendelian Inheritance Objectives: 1. to differentiate the laws of inheritance established by Gregor Mendel 2. to solve problems in genetics demonstrating Mendelian principles The work of Gregor Mendel on garden peas involved testing seven characters individually by producing hybrids from two varieties showing alternative traits such as tall and short as well as green-seeded plant versus a yellow-seeded one. The results of Mendel’s hybridization experiments established the following: a. The F1 showed only one of the alternative traits for any character which was the dominant trait, while the character hidden was recessive. b. Reciprocal crosses gave the same results. c. The trait that did not appear in the F1 reappeared in the F2 but in a frequency of ¼ of the total number. These observations showed that each parent must have contributed equally to each progeny and that in the F2, a 3:1 segregation of the dominant to recessive trait was observed. The F1 thus contains two alternative factors or is heterozygous. These two factors segregate from each other during gamete formation, forming the basis for Mendel’s Law of Segregation. This law thus states that unit hereditary characters occur in pairs and thatin the [285] COURSE BOOK IN GENERAL BIOLOGY formation of gametes, these segregate so that only one member of the gene pair goes into a particular gamete. The diploid number is restored only when the male and female gametes fuse during fertilization to form the zygote. The other law of Gregor Mendel, the Law of Independent Assortment, considers two or more genes/pairs of alleles. This law states that genes for different characters are inherited independently of one another or that the members of one pair of alleles segregate independently of the other pairs. [286] COURSE BOOK IN GENERAL BIOLOGY Name ______________________________ Score ________ Course & Year ______________________ Date __________ Exercise No. 4 A. Probem Solving. Applying the Law of Independent Segregation, solve the following genetic problems. 1. Albinism, the total lack of pigment, is due to a recessive gene. A man and a woman plan to marry and wish to know the probability of their having any albino children. What would you tell them if, a. The man is albino, the woman is normal but her father is an albino? b. Both are normally pigmented, but each has an albino parent? c. The man is an albino but the woman’s family includes no albinos for at least three generations? 2. In garden peas, tall plant is dominant over dwarf. If a plant homozygous for tall is crossed with one homozygous for dwarf, what will be the appearance of the F1? Of the F2? Of the offspring of a cross of F1 with its tall parent? With its dwarf parent? [287] COURSE BOOK IN GENERAL BIOLOGY 3. A tall plant crossed with a dwarf one produces offspring of which about one half are tall and one half are dwarf. What are the genotypes of the parents? 4. Assume that in the families in the following problem, the allele for brown eyes is dominant to that for blue. A brown-eyed man marries a blue-eyed woman and they have eight children, all brown-eyed. What are the genotypes of all the individuals in the family? [288] COURSE BOOK IN GENERAL BIOLOGY Applying the Law of Independent Assortment, solve the following problems. 1. In guinea pigs, rough coat (R) is dominant over smooth coat (r) and black coat (B) is dominant over white (b). R and B are independent genes. Cross a homozygous rough black animal with a smooth, white one. What will be the appearance of the F1? Of the F2? Of the offspring of a cross of the F1 back with the rough black parent? With the smooth white one? 2. In garden peas, tall vine (T) is dominant over dwarf (t), green pods (G) over yellow (g), and round seeds (R) over wrinkled seeds (r). If a homozygous, dwarf, green, wrinkled pea plant is crossed with a homozygous tall, yellow, round one, what will be the appearance of the F1? What gametes does the F1 form? What is the appearance of the offspring of a cross of the F1 with the dwarf, green, wrinkled parent? with its tall, yellow, round parent? [289] COURSE BOOK IN GENERAL BIOLOGY [290] COURSE BOOK IN GENERAL BIOLOGY Lesson 5. Modifications of Mendelian Ratios Objectives: 1. to show particular genetic characters in which the probabilities of the offspring do not follow Mendelian ratios 2. to explainprobabilities of occurrence of traits of offspring in crosses/matings which are not Mendelian in nature. Mendel’s work predominantly demonstrated complete dominance relationships between two different alleles for each gene pair. As the years went by and more genetic experiments have been conducted, some phenotypes and ratios could not be explained on the basis of complete dominance. These did not disprove the principles of Mendel, rather, these extended the understanding of the transmission of traits and have therefore been considered as modifications. These modifications covered the following: a. Incomplete Dominance Dominance is absent and the progeny does not resemble the parents, thus the F1 offspring are intermediate between the two parents. b. Overdominance In this case, the heterozygote exceeds the phenotypic measurements of the homozygous parents. c. Co-dominance [291] COURSE BOOK IN GENERAL BIOLOGY This occurs when both substances appear together in the heterozygote such as in the M-N blood types in man. d. Multiple Alleles These are several possible alternative genes which may be located in a single locus. The alleles act within the same phenotypic range of each other such as that which occurs in the ABO blood groups in human beings. e. Lethal Genes These are genes whose effect is sufficiently drastic to kill the bearers of certain genotypes. f. Gene Interactions Genes are not merely separate elements producing distinct individual effects, but can interact with one another producing entirely different phenotypes. The interactions that result from these result in phenotypic ratios distinctly different from those of independent assortment. [292] COURSE BOOK IN GENERAL BIOLOGY Name ___________________________ Score ___________ Course & Year ___________________ Date ___________ Exercise No. 5 A.Problem Solving. Solve the following problems considered as modifications of Mendelian ratios. 1. In four-o-clock plants, red flower color is incompletely dominant over white (r), the heterozygous plants being pink-flowered. In the following crosses in which the genotypes of the parents are given, what are the gametes produced by each parent, and what will be the flower color of the offspring from each cross? a. Rr x RR b. Rr x Rr c. Rr x Rr 2. In the case of human blood groups, if a person of blood group AB marries one belonging to group O, what will be the blood groups of their children? [293] COURSE BOOK IN GENERAL BIOLOGY 3. In the following case of disputed paternity, determine the probable father of the child: The mother belongs to group B, the child to O, one possible father to A, and the other to AB. [294] COURSE BOOK IN GENERAL BIOLOGY Lesson 6 . The Chemical Basis of Heredity Objectives: 1. to describe the molecular structure of DNA and how it carries out its various activities 2. to explain the Central Dogma of Molecular Genetics DNA as the genetic material was not fully appreciated nor understood until 1953 when James D. Watson and Francis H. C. Crick proposed the molecular structure of DNA. This molecular structure was able to show how the gene could carry its different activities. Deoxyribonucleic Acid or DNA is a polymer composed of repeating nucleotides with each nucleotide made up of a phosphate group and a nucleoside. Each nucleoside is composed of 2-deoxy-D ribose and nitrogen bases. These nitrogen bases are the purines (adenine and guanine) and the pyrimidines (thymine and cytosine). Watson and Crick proposed a double helical structure for DNA. This DNA molecule is made up of two strands, with the strands anti-parallel to each other and coiled together in a plectonemic helix. This helical coil appear as a circular staircase having the same diameter and width of steps, with a connecting railing on either side. Alternating sequences of phosphate and deoxyribose compose the railing and at each sugar, the two strands are bridged by the two nitrogen bases, purine and pyrimidine. A hydrogen bond between the purine and pyrimidine joins the complementary polynucleotide strands. [295] COURSE BOOK IN GENERAL BIOLOGY Structure of a DNA Molecule Source: [296] COURSE BOOK IN GENERAL BIOLOGY Name _____________________________ Score ___________ Course & Year _____________________ Date ___________ Exercise No. 6 A. Essay. Explain the following briefly. 1. Why is specificity in base pairing one of the most important features of the Watson and Crick model of DNA? ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________ 2. How would you differentiate the organization of DNA in prokaryotic and eukaryotic chromosomes? ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________ 3. How would you differentiate the following enzymes involved in the replication process from each other? a. DNA helicase – DNA gyrase [297] COURSE BOOK IN GENERAL BIOLOGY _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _________________________________ b. DNA polymerase I- DNA polymerase III _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _________________________________ c. Primase – DNA ligase _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ _________________________________ [298] COURSE BOOK IN GENERAL BIOLOGY Name ______________________________ Score ___________ Course & Year _____________________ Date ____________ Exercise No. 2 A. Fill in the blanks. 1. During semi-conservative DNA replication, information is transferred from DNA to _________________. 2. The _________________ is a single-stranded molecule composed of nucleotides which code the sequence of amino acids in protein synthesis. 3. The __________________ is a “clover leaf” structure consisting of 75-80 nucleotides and has unpaired bases at the amino acid arm and in the loop opposite the anti-codon arm. 4. The gene that carries the message for the amino acid sequence of a specific protein is called ____________________. 5. A _________________ gene codes for the amino acid sequence of a specific protein. 6. A _______________ gene determines whether or not the structural genes will be transcribed. [299] COURSE BOOK IN GENERAL BIOLOGY 7. The _________________ functions as the master copy upon which the synthesis of daughter DNA molecule occurs. 8. The main chemical _________________, components of chromosomes ___________________ are and __________________. 9. A ___________________ consists of nucleotides linked by 3’-5’ phosphodiester bonds. 10. A _________________ fork is formed when the DNA double helix unwinds and separates to form two single-stranded templates. [300] COURSE BOOK IN GENERAL BIOLOGY Lesson 7. Human Genetics Objectives: 1. to identify the causes of chromosomal aberrations in human beings 2. to determine the kinds of chromosomal abnormalities resulting from abnormal chromosome numbers and structures Humans have been awkward subjects for genetic studies for quite some time. Having a long life cycle and comparatively smaller number of progeny, they were not considered to be feasible subjects for use in standard research techniques in genetics. Added to this is the fact that humans are not able to subject themselves to rigorous experimental conditions and neither do they desire to do so. However, there have been some circumstances that now have made researches in human genetics possible. Techniques for examining human beings more thoroughly have been developed through intensive medical researches. Technical methods such as culturing human somatic tissues for cytological investigations have enabled analysis in areas of human genetics previously thought to be closed to effective investigation. Because of man’s interest in himself, this has resulted in a great deal of knowledge of his biochemistry, morphology, anatomy, physiology and behaviour. Humans are not exempt from chromosomal aberrations. These have particularly been of great interest in the field of medicine. Reports have shown that chromosome anomalies occur in 0.48% of all newborn infants and that at least 25% of spontaneous miscarriages have resulted from chromosomal aberrations. Various studies have likewise shown that various chemical steps in human metabolism are gene-controlled. Knowledge of [301] COURSE BOOK IN GENERAL BIOLOGY biochemical genetics has therefore been able to provide an increasingly sound basis for dealing with some human genetic defects. [302] COURSE BOOK IN GENERAL BIOLOGY Name ______________________________ Score ___________ Course & Year _____________________ Date ___________ Exercise No. 7 A. Identification. Give the cause of the chromosomal aberration or defect in the following cases. 1. Polyploidy = ________________________________________________________ _______________________________________________________ ________________________________________________________ ___ 2. Down’s syndrome = ________________________________________________________ _______________________________________________________ ________________________________________________________ ___ 3. E Trisomy syndrome = ________________________________________________________ _______________________________________________________ ________________________________________________________ ___ 4. Turner’s syndrome = _______________________________________________________ [303] COURSE BOOK IN GENERAL BIOLOGY ________________________________________________________ ________________________________________________________ ___ 5. Klinefelter’s syndrome = ________________________________________________________ _______________________________________________________ ________________________________________________________ ___ 6. Jacob syndrome = _______________________________________________________ ________________________________________________________ ________________________________________________________ ___ 7. Cri-du-chat syndrome = ________________________________________________________ _______________________________________________________ ________________________________________________________ ___ 8. Muscular dystrophy = ________________________________________________________ ________________________________________________________ ________________________________________________________ ___ [304] COURSE BOOK IN GENERAL BIOLOGY 9. Hermaphroditism = ________________________________________________________ ________________________________________________________ ________________________________________________________ ___ 10.Philadelphiachromosomes = ________________________________________________________ ________________________________________________________ ________________________________________________________ ___ B. Essay. Explain how the following errors of metabolism/protein alterations due to mutations occur in the following cases. 1. Galactosemia ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________ 2. Phenyketonuria ________________________________________________________ ________________________________________________________ ________________________________________________________ [305] COURSE BOOK IN GENERAL BIOLOGY ________________________________________________________ _____________________________ 3. Favism ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________ 4. Sickle cell anemia ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________ 5. Cystic fibrosis ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ _____________________________ [306] COURSE BOOK IN GENERAL BIOLOGY Chapter 9 BIOTECHNOLOGY [307] COURSE BOOK IN GENERAL BIOLOGY [308] COURSE BOOK IN GENERAL BIOLOGY Lesson 1: Overview of Biotechnology Objectives: 1. to define biotechnology and identify products generated through it 2. to differentiate between traditional and modern biotechnology and justify thisclassification Biotechnology is defined as the use of living things or their parts or products to improve other living organisms or make products that are useful to man. Biotechnology had been used by man since time immemorial initially through fermentation to improve food flavor. Later on, selection, domestication and hybridization of plants and animals were consciously practiced to cope with the requirements of growing human population, increasing quantity and improving quality of food at the same time. For years, man honed his skills in a traditional way to produce desirable or beneficial products. The continuous developments in genetic engineering have resulted to the modernization of biotechnology, overcoming interspecific barriers of traditional hybridization. Although not a panacea, it is foreseen as a solution to a great number of problems due to the almost limitless options that it could offer. Modern biotechnology provides great prospects for agriculture (great potential for food sufficiency), industry and energy source augmentation, environmental protection, health and wellness and even provides solutions to social, ethical and legal issues. [309] COURSE BOOK IN GENERAL BIOLOGY Today, the synergy of traditional and modern biotechnology is being explored to generate products that have tremendous impact on various aspects of our lives. Traditional biotechnology includes the most primitive type of accidental fermentation process which is still being used now to produce varieties of food products, such as cheese, “bagoong” (fish paste), “patis” (fish sauce), wine, “nata de coco” (coconut gel), fermented fish and vegetables. This technology was later applied in the field of medicine to produce antibiotics and vaccines from microorganisms. In agriculture, traditional plant and animal breeding is still being used. Modern biotechnology makes use of more advanced knowledge on molecular biology. Some techniques, such as DNA fingerprinting and somatic nuclear transfer do not involve gene manipulation. Molecular biology kits for the detection and diagnosis of diseases and cloned animals are products of modern biotechnology. The most recent modern biotechnology employs methods of genetic engineering that essentially construct and design hereditary units of information to produce desired outcomes in a predictable and controllable way in target organisms. A plant, animal or microorganism that has received a constructed or altered gene which shows a new characteristic is called a genetically modified or transgenic organism. [310] COURSE BOOK IN GENERAL BIOLOGY Name _______________________________ Score ________ Course & Year ______________________ Date _________ Exercise No. 1 A. Answer the following questions as required. 1. List down at least 10 biotechnology products that you use at home. a. f. b. g. c. h. d. i. e. j 2. In your own understanding, how does traditional biotechnology differ from modern biotechnology? Cite a product produced traditionally but has been improved through modern biotechnology. [311] COURSE BOOK IN GENERAL BIOLOGY Exercise No. 2 TRUE or FALSE. Write true if the statement is correct and write false, if otherwise, on the spaces provided for. ________ 1. Dolly, the sheep is a product of modern biotechnology, therefore, it is a genetically modified organism. ________ 2. DNA fingerprinting is a molecular biology tool used in forensics that involves genetic engineering. ________ 3. Cheese is a product of traditional biotechnology that could be improved further by modern biotechnology. ________ 4. The production of insulin by Eschericia coli is an indication that human genes can be expressed in microorganisms. ________ 5. The first agricultural biotechnology product being commercialized in the Philippines is Bt corn, having yield advantage over the non-transgenic hybrid because it bears more ears than the latter. [312] COURSE BOOK IN GENERAL BIOLOGY Lesson 2: The Genetic Material and Central Dogma of Molecular Biology Objectives: 1. to illustrate and describe the components of the genetic material 2. to trace how DNA is translated into proteins The genetic material in organisms is the deoxyribonucleic acid (DNA) which is found integrated with proteins in chromosomes inside the nucleus of a cell. The DNA molecule consists of fragments or hereditary units called genes which are passed from parents to their offspring. They are responsible in the inheritance of traits such as size, shape, color, built and other characteristics of microorganisms, plants and animals, including man. The DNA in all cells of an organism are identical. In plants, for example, DNA in the roots is the same as that of the leaves and fruits. The structure or appearance of these parts, however, differ because not all of the genes are active or expressed at the same time in different cells. Genes code for proteins and the sum of protein products generated at the same time in a tissue or organ would define the trait or characteristic of that particular part. Collectively, the differential expression of genes and production of proteins in the different tissues and organs is manifested in the phenotype of the individual. The building blocks of DNA are called nucleotides consisting of sugar residues, phosphate groups and nitrogenous bases categorized into [313] COURSE BOOK IN GENERAL BIOLOGY purines (adenine and guanine) and pyrimidines (thymine and cytosine). The sequence of nucleotides along the stretch of the DNA contains the chemical code of information as to how the organism would grow and develop. The complementary base pairing in the DNA is specific, such that adenine specifically pairs with thymine and guanine specifically pairs with cytosine. This allows for replicability of genetic information, a characteristic explored in genetic engineering. The Central Dogma of Molecular Biology states that the code of the DNA is used for the production of proteins by the organism in a two-step process. In eukaryotes, the processes involved are compartmentalized such that replication and transcription of DNA by messenger RNA (mRNA) take place in the ribosomes of the cytoplasm. In the cytoplasm, transfer RNA (tRNA) and ribosomal RNA (rRNA) facilitate the process. In prokaryotes, since there is no distinct nuclear membrane, the processes occur simultaneously and are not spatially separated. [314] COURSE BOOK IN GENERAL BIOLOGY Name __________________________ Score ___________ Course _________________________ Date ____________ Exercice No. 1 A.Essay: Answer the following questions as required. 1. Describe DNA and state its properties that make it an ideal genetic material. 2. Fill out the following table to differentiate a DNA from an RNA. Bases of DNA comparison 1. Number of strands 2. Location in the [315] RNA COURSE BOOK IN GENERAL BIOLOGY cell 3. Function 4. Nitrogen bases 5. Sugar residue 3. Name the three types of RNA and specify their functions during protein synthesis. 4. Discuss in detail the steps involved in decoding of DNA and synthesis of proteins. [316] COURSE BOOK IN GENERAL BIOLOGY Lesson 3. Tools of Genetic Engineering and Benefits of Gene Manipulationj Objectives: 1. to define genetic engineering and genetically modified organisms 2. to describe the tools or techniques used in the creation of recombinant DNA 3. to discuss the advantages of genetic engineering Genetic Engineering involves human mediated artificial transfer of gene(s) from one organism to another with the purpose of making the recipient synthesize a needed chemical, carry out a useful process or to produce a desirable characteristic that it does not originally possess. Genetic engineering is also referred to as recombinant DNA technology. The recipients of the altered gene are called Genetically Modified Organisms (GMOs) or transgenics. Genetic engineering uses various tools in the exploration of the DNA so as to create new biotechnology products. Various techniques, such as splicing DNA with restriction enzymes, amplification of traces of DNA through polymerase chain reaction (PCR), visualization and separation of fragments (DNA or proteins) through gel electrophoresis, DNA sequencing, hybridization techniques, DNA microarrays to monitor expression of genes are being used to study the cell and its components at different levels. [317] COURSE BOOK IN GENERAL BIOLOGY The benefits of recombinant DNA technology include the following: 1. It takes a shorter period of time to produce an improved product. 2. There are almost limitless possibilities due to wider gene pool. Interspecies combination of genes is possible. 3. Introduction of new characteristics is more precise. 4. Results are predictable and controllable. [318] COURSE BOOK IN GENERAL BIOLOGY Name _______________________________ Score _________ Course & Year ______________________ Date __________ Exercise No. 1 A. Matching Type:Match the following biotechniques or tools (A) with their function/uses (B): A B ______ 1. Polymerase Chain Reaction a. determines arrangements of nucleotideswithin the DNA and to detect mutation ______ 2. DNA sequencing b.amplifies or makes millions of copies of small quantities of DNA ______ 3. Hybridization technique c. cuts DNA ______ 4. Restriction enzyme d.spots specific DNA sequences in an enormous mixture of DNA ______ 5. Gel electrophoresis e. separates fragments of DNA or proteins B. Essay: Answer the following questions briefly. [319] COURSE BOOK IN GENERAL BIOLOGY 1. How are GM microorganisms, plants and animals made? Is there any difference in the biotechniques used when cloning a unicellular organism and multicellular organism? 2. Name at least five (5) most popular specimens used in genetic manipulation researches. [320] COURSE BOOK IN GENERAL BIOLOGY Lesson 4. Applications of Genetic Engineering Objective: 1. to discuss the specific benefits derived from a particular genetically modified product 2. to compare genetically modified products to their non-genetically modified counterpart A. Agriculture – Food security Modern biotechnology addresses the problems on food quantity and quality. The so-called first generation GM crops which possess traits of insect resistance, virus resistance and herbicide tolerance have yielded significant benefits, such as higher produce and farm profit and conservation of the environment. Two or more traits may be combined such as herbicide tolerance and insect resistance in corn. The following are some of the commercially available crops with their corresponding traits: Crop 1. Corn Introduced Trait herbicide tolerance insect resistance combined herbicide tolerance and insect resistance 2. Soybean herbicide tolerance 3. Canola herbicide tolerance 4. Papaya virus resistance [321] COURSE BOOK IN GENERAL BIOLOGY 5. Squash virus resistance Other products in the pipeline include the second generation crops with improved nutritional qualities, such as high-iron rice and golden rice or crops that would address dietary deficiencies of people and other desirable substances such as antioxidants, vaccines and other pharmaceuticals. Researches are also on-going to improve tolerance of crops to various environmental stresses, such as drought, flooding, salinity and high irradiation. For livestock, poultry and aquaculture biotechnology techniques are being exploited in order to diagnose diseases promptly and accurately. Genetic engineering is also used for the production of animal vaccines and growth hormones to improve the yield and quality of animal products. B. Environmental Protection Genetically modified organisms that would degrade various forms of solid wastes and toxic substances are being explored to address large scale problems of environmental pollution. Bioremediation makes use of microorganisms, while phytoremediation makes use of plants to remove toxic materials such as pesticides, herbicides and metals from the environment. The production of insect resistant GM plants is an environment friendly technology and reduces the use of non-biodegradable metal-based pesticides. Likewise, the use of herbicide resistant crops is also advantageous [322] COURSE BOOK IN GENERAL BIOLOGY to the environment. It decreases soil tillage thus preventing soil erosion and preserving soil fertility. Production of biodegradable plastics using microorganisms and plants is being studied. C. Health and Medicine Naturally produced antibiotics have been rare, thus, man has resorted to the use of laboratory synthesized antibiotics which are expensive. With the use of genetic engineering, scientists can develop microorganisms which can serve as factories, producing large quantities of antibiotics with the desired chemical structure. Other pharmaceutical products generated through this modern technique are the following: 1. Human insulin - to treat human diabetes 2. Human growth hormone - to treat some form of dwarfism and has potential in the treatment of wounds and burns Molecular biology techniques are now being used to develop kits for the detection and diagnosis of inherited diseases, such as the Newborn Screening. Biotechnology approaches are also being explored for the production of vaccines against microbial pathogens causing human diseases like chicken pox, AIDS, cholera, gonorrhea, typhoid fever, tetanus, malaria and schistosomiasis, among others. D. Industrial Biotechnology Genetic engineering is being explored for the production of novel compounds and increase synthesis of commercially high value products in [323] COURSE BOOK IN GENERAL BIOLOGY microorganisms, plants and animals. Researches on the pipeline include the following: • Screening industrially important enzymes from thermophilic microorganisms (which could possibly degrade cellulose, mannan, xylan and lignin • Yeast strains that are more efficient in fermentation • Use of enzymes instead of acid in bleaching paper, making stonewash denims, paper and cotton fabrics • Use of biological rather than chemical means in the production of vitamin B and the antibiotic, Cephalexin Alternative polymers (renewable and biodegrable) to replace plastics and petrochemical products Astaxanthin pigment producing tobacco flower Cotton plants that can synthesize polyester/ cotton blend in the boll Modified Arabidopsis thaliana and cotton that can produce biodegradable plastic precursor E. Forensics The molecular biology technique, DNA fingerprinting (also known as genetic profiling) is now the most potent tool in human identification as it provides a very accurate evidence for criminal investigation, paternity suits and identification of disaster victims. The relatedness of the DNA analysis of a crime suspect with the DNA of a biological sample in the crime scene may either confirm his involvement or innocence. Comparison of DNA [324] COURSE BOOK IN GENERAL BIOLOGY markers from a child and its close relatives establishes kinship. DNA fingerprinting is the most acceptable and rapid method of identification of victims of mass disasters.DNA fingerprinting is thus a reliable and rapid approach for the resolution of crimes and has a great potential for serving justice to whom it is due at the right time. [325] COURSE BOOK IN GENERAL BIOLOGY [326] COURSE BOOK IN GENERAL BIOLOGY Name ___________________________________ Score ____________ Course & Year ____________________________ Date _____________ Exercise No. 1 A.Essay: Answer the following questions briefly. 1. List down 10 commercially available (either locally or globally) biotechnology products and enumerate their specific uses. 2. Identify five biotechnology products that serve for multiple purposes. Describe their respective applications. e.g. a) insect resistant corn [327] COURSE BOOK IN GENERAL BIOLOGY assures increase in yield and offers protection to the environment. b) production of biodegradable plastics provides a ready source of a much-needed industrial material and serves as environment-friendly product as well. [328] COURSE BOOK IN GENERAL BIOLOGY Lesson 5: Regulation of GMOs Objectives: 1. to enumerate and describe some of the foreseen risks of genetic manipulation. 2. to cite the involvement of various agencies in the regulation of GMO and specify their function 3. to discuss ways by which risks on GMOs could be mitigated Just like other emerging technologies and scientific developments, modern biotechnology has risks, but these can be identified and managed. In the Philippines, guidelines for various endeavors related to GMOs particularly crops, are dictated by regulatory agencies and implement them with other identified agencies. These are the following: 1. Guidelines for contained experiments laid by the National Committee on Biosafety of the Philippines (NCBP) in the Philippine Biosafety Guidelines 2. Guidelines for field testing embodied in the Guidelines on Planned Release of GMOs and Potentially Harmful Exotic Species Implementation of these guidelines is undertaken by the Institutional Biosafety Committee (IBC) and the NCBP 3. Guidelines on the commercial importation and large scale release of genetically modified crops and plant products contained in the Administrative order issued by the Department of Agriculture (DA). These guidelines are implemented by DA in coordination with various appropriate agencies. [329] COURSE BOOK IN GENERAL BIOLOGY The concerted efforts of scientists, GMO producers and the government ensure the safety of novel products for consumption. Starting with the research phase until commercialization, risk management measures are prescribed to avoid or reduce possible risks. So far, the safety assessment process undertaken for GM foods is far more rigid than that for conventionally bred crops. Likewise, the environmental safety of commercially available GMOs is thoroughly evaluated prior to their release from their country of origin. [330] COURSE BOOK IN GENERAL BIOLOGY Name ______________________________ Score _________ Course _____________________________ Date __________ Exercise No. 1 A.Essay:Answer the following questions. 1. Enumerate the risks of utilizing GMOs and suggest means for their mitigation. 2. Identify the various agencies involved in the regulation of GMOs and identify the points of regulation implemented by them. [331] COURSE BOOK IN GENERAL BIOLOGY 3. In your opinion, are the policies and guidelines for GMOs in the Philippines sufficient to safeguard the consumers and the environment? Explain your answer. [332] COURSE BOOK IN GENERAL BIOLOGY Chapter 10 Communities of Life and Ecosystems [333] COURSE BOOK IN GENERAL BIOLOGY [334] COURSE BOOK IN GENERAL BIOLOGY Lesson 1: Basic Concepts in Ecology Objectives: 1. to discuss the basic concepts in ecology 2. to differentiate the levels of organization in ecology 3. to classify organisms based on the levels of organization Definition of terms and concepts in ecology Ecology is the study of the interaction between living things and their immediate environment. Environment refers to all external factors that may affect an organism. As these factors undergo changes, the environment varies. Biotic factors refer to the living components of the physical world. These living things include microscopic as well as unicellular and multi-cellular organisms. Abiotic factors refer to the non living things found in the physical world that have effects of living things. Habitat is the specific place where an organism resides while a niche refers to the functional role of an organism in its habitat. [335] COURSE BOOK IN GENERAL BIOLOGY Levels of organization in ecology Species refers to organisms that reproduce their own kind, while population is a group of individual species living together in a given period of time and space. Community refers to a group of different populations of organisms living in a given space and time, while ecosystem is composed of different communities interacting with abiotic factors. Biosphere is composed of complex ecosystems within the atmosphere, hydrosphere and lithosphere of the earth that supports life. [336] COURSE BOOK IN GENERAL BIOLOGY Name:__________________________ Score___________ Course & Year: _________________ Date __________ Exercise No. 1 A. Crossword Puzzle: Complete the crossword puzzle below. 1 4 5 2 3 6 7 8 9 10 11 12 13 14 15 16 Across: Down: 2. Dry condition of a physical environment 1. The acidity or alkalinity of a medium that affect microbial growth 4. Abiotic factor necessary for photosynthesis 2. Abiotic factor with more H++ ions 7. Precipitation 3. Male duck species 9. Bird species with webbed feet 5. Six legged invertebrate species [337] COURSE BOOK IN GENERAL BIOLOGY 10. A catadromous fish species 6. Plant species with single woody stem 12. Spaces occupied by biotic factors 8. Source of radiation 14. Many seeded fruit tree species 15. Particulates in the atmosphere 16. Water hole that contains microbes B. Group the organisms in the box below as to their distribution in the biosphere using the following list of biotic organisms. Bacteria, fungus, sponges, coelenterates, insects, mollusks, fishes, amphibians, reptiles, birds, mammals Parts of the biosphere Organisms thatsurvive Atmosphere Lithosphere [338] COURSE BOOK IN GENERAL BIOLOGY Hydrosphere C. Classify the following based on level of organization (eg. species, population, or community). Write your answer on the blank provided before each number. _________________1. Herd of swine _________________2. School of fish in a river _________________3. Tilapia in a fishpond _________________4. Swarm of locusts _________________5. Groups of flying insects feeding on tree foliages _________________6. Flocks of migrating wild ducks _________________7. Endangered wild deer _________________8. Mahogany trees planted along the highway _________________9. Weeds in a rice field _________________10. Pechay plants in garden plots _________________11. Fruit trees in a farm [339] COURSE BOOK IN GENERAL BIOLOGY _________________12. Mimosa pudica along the sandy roadsides _________________13. Vegetables in a farm _________________14. Varieties of papaya plants in the backyard _________________15. Santan plant [340] COURSE BOOK IN GENERAL BIOLOGY Lesson 2: Population Change in Size Objectives 1. to identify various factors affecting population 2. to explain the consequences of population change to the physical environment Factors that increase population size Reproduction is the natural means of increasing a population coupled with food abundance which can be added upon by migration or movement of mobile organisms to a certain place as response to seasonal changes. A gradual increase in population may occur when birth rate is higher than death rate within a given population. Factors that decrease population size A population is naturally decreased by a high death rate. Aside from this, predation and emigration can reduce population to a reasonable number. Further, natural calamities can destroy natural habitats and reduce the number of a population. Effects of population change to the environment Any change in a given population has a corresponding effect on the organism’s immediate physical environment. Increase in population means more resources needed and less space since the environment is limited. Increase in upland population may lead to forest denudation, and over cultivation in lowlands can result to chemical nutrient depletion. Likewise, [341] COURSE BOOK IN GENERAL BIOLOGY decrease in plant populations can disrupt nutrient cycles, affect air quality and even temperature. [342] COURSE BOOK IN GENERAL BIOLOGY Name:__________________________ Score ___________ Course & Year: _________________ Date ___________ Exercise No. 2 A. Underline the correct answer from the choices found to make each statement correct. 1. Spoiled cooked rice will increase the population of (molds, rats, frog, cat). 2. A wild fire during summer time usually decreases the population of (grasses, goats, dogs). 3. Nitrate pollutants fishermen, increase the population of (tilapia, algae, corals) 4. When the birth rate is the same as the mortality rate, there will be (increase, no change, decrease) in the population. 5. When emigration rate is lower than that of migration, then the population (increases, remains the same, decreases). 6. When the population of rats increase, the existing number of cats naturally (increase, decrease, remains the same) 7. In an enclosed pastureland with abundant grasses, a population of cows (increases steadily, increases then decreases, remains the same) [343] COURSE BOOK IN GENERAL BIOLOGY 8. Foot and Mouth Disease can usually reduce populations of (chicken, pig, fish). 9. (Coconut, Cogon, Gumamela) can naturally increase its population in a short period of time. 10. (Volcanic eruption, famine, drought) is a natural calamity that dries water sources affecting both terrestrial plant and animal up populations. B. Essay. Answer the following questions briefly. 1. Give and discuss at least two natural calamities that decrease human population. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________ 2. The tropical region is the most populated part of earth. Why is this so? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________ [344] COURSE BOOK IN GENERAL BIOLOGY Lesson 3: Community Interactions Objectives: 1. to identify the different forms of interaction in a community 2. to differentiate the different levels of interactions 3. to discuss the ecological importance of interactions Forms of interactions Different forms of species interactions in a community Interactions Species A Species B Parasitism + - Mutualism + + Commensalism + 0 Competition + - Predation + - Legend: + Benefited, -Harmed, 0 Not affected (neutral) Levels of Interactions 1. Intraspecies interaction [345] COURSE BOOK IN GENERAL BIOLOGY This interaction occurs when individuals of the same species interact as in the case of a horse population grazing in the same pastureland. This holds true for same plant species that grow in the same space competing for light as well chemical nutrients. 2. Interspecies interaction This type of interaction is one which occurs between and among different species. Grazing animals such as cattle may compete with horses for grasses during interspecies competition. Different sessile and plant species do compete in terms of chemical nutrients and space. In competition, the well adapted organisms usually survive while the weaker ones perish. In predation, an aggressive species depends on weaker prey asits source of food. A green snake swallowing a frog as its food is a typical example of this interaction. In some instances, a predator can prey on different prey species. Two interdependent species may likewise live in symbiotic relationship. There are two types of symbiosis observed in nature namely, commensalism between two species where one is benefited but the other is not harmed; and mutualism where both species are benefited from the relationship. [346] COURSE BOOK IN GENERAL BIOLOGY Name:__________________________ Score___________ Course & Year: _________________ Date: ____________ Exercise No. 3 A. Identify the type of interactions below. Write your answer on the blank opposite each item. 1. Goat and cogon grass ______________________________________ 2. Cow and carabao in pastureland _________________________________ 3. Mango trees and carabao grass in an orchard _______________________ 4. Acacia tree and an epiphytic fern ________________________________ 5.Man and Lactobacillus protectus_________________________________ 6. Dog and fleas ___________________________________________ 7. Termite and bacteria _____________________________________ 8. Dog and cat________________________________________________ 9. Rice plant and leafhopper ____________________________________ [347] COURSE BOOK IN GENERAL BIOLOGY 10. “Balete”tree and birds_______________________________________ 12. Mushroom and worms in decomposing wastes____________________ 13. Bacteria and virus in a human host_______________________________ 14. Golden snail and rice plants____________________________________ 15. “Tilapia” and “carpa” in a fishpond_____________________________ B. Answer the following essay questions briefly. 1. Insects compete with humans. Cite two situations in which this occurs. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ _______________ 2. Field snakes prey on newborn rats. What happens if snake populations decrease? ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ________________ [348] COURSE BOOK IN GENERAL BIOLOGY Lesson 4: Community disturbances and successions Objectives: 1. to show anthropogenic and natural community disturbances 2. to discuss the effects of human activities to communities of organisms 3. to trace community succession from a disturbed community Community disturbances Community disturbances refer to external factors that can disrupt the existing interactions in a given community that pave way for new species to be established. These disturbances can be classified as anthropogenic when caused by human activities, and natural disturbances when these are caused by natural forces such as typhoons and earthquakes. Anthropogenic disturbances The continuous increase in human population means additional needs. This leads to direct exploitations of natural resources in forests, grasslands, coastal areas, wetlands, marshes, seas, oceans and rivers. Natural disturbances The earth is in constant change causing a lot of disturbances to living organisms. In the Philippines, typhoons, volcanic eruptions and earthquakes are common occurrences. Recently, wildfires hit Australia and America. Nowadays, climate changehas become a global concern. [349] COURSE BOOK IN GENERAL BIOLOGY Community successions Because of the dynamic characteristic and instability of ecosystems, populations constituting them do not remain the same. Gradual changes in the community take place over time and are called ecological successions. A totally disturbed community undergoes the following ecological successions. a. Primary succession starts when an uninhabited site is colonized by pioneer species. These are able to grow in exposed areas that have intense sunlight, wide variations in air temperature and nutrient-poor soil. They are usually small, low-growing, with short life cycles and produce small seeds which are quickly dispersed from the parent plants. When a volcanic eruption, for example, changes the landscape of an island, pioneer species eventually invade such habitat followed by a series of organisms over a period of time. b. Secondary successions, on the other hand, are characteristic of abandoned fields and parts of established forests where falling trees or other disturbances have opened canopies of leaves enabling sunlight to reach the forest floor. In this type of succession, many plants grow from seeds or seedlings that are already present when the process has started. Climax community [350] COURSE BOOK IN GENERAL BIOLOGY When certain groups of organisms become dominant and stable for a period of time, this comprises a climax community. In a typical plant ecological succession, tree species compose a climax community; Narra and acacia trees dominate a tropical dipterocarp forest; Pinus species in pine forest while Dacrycarpus imbricatus,Lithocarpus and Syzygium species in mossy forest. [351] COURSE BOOK IN GENERAL BIOLOGY [352] COURSE BOOK IN GENERAL BIOLOGY Name:_______________________________ Score_________ Course & Year: _________________ Date: __________ Exercise No. 4 A. Multiple Choice: Answer the following questions by encircling the letter that corresponds to the best answer. 1. What is the natural disturbance that may cause felling of trees, forest soil erosion and flooding of wetlands? a. rain b. typhoon 2. c. hurricane What construction disturbs a wetland community? a. cell sites b. subdivisions 3. c. commercial d. River system b. Illegal logging c. mud flow d. lava What causes the disturbance of forest communities? a. employment 6. d. superhighway What caused the destruction of the slopes of Mount Pinatubo in 1990? a. lahar flow 5. c. golf courses In what areas is the Kaingin system a common practice? a. rural b. Urban 4. d. tornado b. poverty c. bats d. technology What organism would be the first aquatic animal species to live in a rain fed fishpond? a. frog b. tilapia c. golden snail [353] d. turtle COURSE BOOK IN GENERAL BIOLOGY 7. In an eroded mountain, what grow first as a pioneer community? a. shrubs 8. c. bushes d. trees What dominates a stable grassland community? a. vines 9. b. mosses b. bamboos c. grasses d. horsetails Lichen communities can survive in what type of extreme habitat? a. tundra b. polar cap c. estuary d. desert 10. Dam construction can permanently submerge what type of communities? a. coastal b. low lying areas c. upland d. River bank B. Arrange the following plant species that would grow in succession in a dipterocarp forest that has undergone erosion due to human interventions. Bushes, shrubs, lichens, mosses, ferns, herbs, vines, rain tree, narra trees, grasses Primary succession Secondary succession Climax community species species Species [354] COURSE BOOK IN GENERAL BIOLOGY C. React to the following statement: A community undergoing secondary succession has more diverse plant species than a stable community. [355] COURSE BOOK IN GENERAL BIOLOGY [356] COURSE BOOK IN GENERAL BIOLOGY Lesson 5: Ecosystems Objectives: 1. to describe the concept of ecosystems 2. to trace the flow of energy in an ecosystem 3. to trace nutrient cycle within a ecosystem 4. to predict the consequences of human activities to the ecosystem Ecosystem refers to the interactions among communities of organisms with the varied physical factors in their immediate environment. The figure below illustrates a grassland ecosystem showing animal and plant species interacting with the environment. Figure 1. A grassland ecosystem showing animal and plant species interacting with the environment [357] COURSE BOOK IN GENERAL BIOLOGY Energy flow within the ecosystem Energy flows in the ecosystem following the Law of Conservation of Energy, that is, energy is transformed from one form to another. This transformation occurs when energy is passed through the different trophic or feeding levels as illustrated in the figure below. Some of this energy is used up at the different levels and converted to heat that dissipates into space, a process known as entropy. Fig. 2. Energy flow within the ecosystem [358] COURSE BOOK IN GENERAL BIOLOGY Food web A food web is the ecosystem’s mechanism for circulating and recycling energy and materials. The different trophic levels combine to form a food web. A series of food chains in an ecosystem create this complex web as shown in the figure below. Fig. 3. The Food Web Nutrient Cycles Unlike energy that is supplied by solar radiation, chemical nutrients are fixed in a given ecosystem that needs to be recycled back. This recycling [359] COURSE BOOK IN GENERAL BIOLOGY involves biological, physical and chemical processes better known as biogeochemical cycles. Major nutrient cycles are illustrated below. Fig. 3. The Carbon and Oxygen Cycle Fig. 4.The Nitrogen cycle Source: http://www.windows2universe.org/earth/climate/ima ges/nitrogencycle.jpg [360] COURSE BOOK IN GENERAL BIOLOGY Figure 5. Phosphorous cycle Source: http://bioweb.wku.edu/faculty/ameier/phoscy cle.gif Fig. 6. Sulfur cycle Source: http://homepages.nyu.edu/~pet205/sulfur3.gif [361] COURSE BOOK IN GENERAL BIOLOGY Human activities that disrupt the nutrient cycles One of the most affected nutrient cycles is the carbon cycle. Carbon dioxide is naturally produced due to decomposition and volcanic eruptions. However, greater amounts of carbon dioxide are being released and accumulated in the atmosphere because of fire, fossil oil-powered machines used in factories, transportations and generation of energy. Besides, the destruction of plant covers due to burning and clearing lessens the capacity of terrestrial ecosystems to recycle back carbon. Too much carbon dioxide concentration in the atmosphere is believed to cause the “green house effect” that increases global temperature bringing about global warming. Farmers use phosphate and nitrate fertilizers to increase food supply to meet the demand of the ever increasing human population. Excess fertilizers leach out and disrupt the normal functioning of most aquatic ecosystems as in the case of eutrophication. [362] COURSE BOOK IN GENERAL BIOLOGY Name:__________________________ Score __________ Course & Year: _________________ Date __________ Exercise No. 5 A. Multiple Choice: Answer the following questions by encircling the letter that corresponds to the best answer. 1. Of the following, which is not a physical component of an ecosystem? a. biotic factors b. abiotic factors c. photosynthesis d. microorganisms 2. What normally happens to the energy flowthrough the ecosystem? a. increases b. diminishes c. remain the same 3. e. evaporates What is the beginning of energy flow in an ecosystem? a. decomposition b.photosynthesis c. biogeochemical cycle d. respiration 4. What is the end process of energy flow in an ecosystem? a. decomposition b.photosynthesis c. biogeochemical cycle d. respiration 5. What is the ultimate source of energy that flows in an ecosystem? a. solar radiation b. chlorophyll c. ATP 6. d. DNA What is the form of energy stored by producers in the ecosystem? a. mechanical b. heat c. chemical d. light 7. What is the lowest form of energy dissipated into space? a. mechanical b. heat c. chemical d. light 8. If photosynthesis is to oxygen, which is to respiration? a. nitrogen b. carbon c. carbon dioxide [363] d. hydrogen COURSE BOOK IN GENERAL BIOLOGY 9. What cycle involves geological processes that take a long period of time? a. Nitrogen b. Phosphorous c. Carbon d. Sulfur 10. Which nutrient cycle requires biological agents found in soil? a. Nitrogen b. Phosphorous c. Oxygen d. Carbon II. Group the following marine organisms listed as to their respective feeding levels using the table below. Worms , Phytoplankton, Krills, Orcas, Bacteria, Dugong, Seaweeds Sharks, Whales, Dolphins, Squids, Snails, Small fishes, Diatoms, Kelp Producers Primary Secondary Consumer Consumer Tertiary Consumer [364] Decomposer COURSE BOOK IN GENERAL BIOLOGY III. Essay. 1. Discuss at least two possible scenarios if carbon dioxide concentration increases continuously in the atmosphere. 2. Propose at least three measures to lessen carbon dioxide concentration in the atmosphere. 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