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1 Themes of Life Vocabulary Biology Biotechnology Forensics Homeostasis Organ Organ system Organism Scientific principle Science theory hypothesis eukaryote prokaryote Concepts to Know Characteristics of Life: Living things are made of cells – Smallest unit of an organism that is considered alive – Can be unicellular (bacteria) or multicellular (humans) Living things reproduce – Asexual: formation of a new organism from one parent. Offspring is a clone – Sexual: two cells from different parents unite to produce the 1st cell of new organism Living things are based on a universal genetic code – Based on 1 molecule that is almost identical in every organism on earth: DNA (Deoxyribonucleic Acid) Living things grow and develop – Growth: an increase in size of an organism – Development: progression through a life cycle Living things obtain materials and use energy – Autotroph: obtains energy from the sun – Heterotroph: obtains energy from consuming other organisms. Living things respond to environment ex. Find shelter from rain ex. Hibernating to survive the winter ex. Produce toxins to ward off predators Living things maintain a stable internal environment – Homeostasis: keeping internal condition stable relative to the external environment Living things change over time (evolve) – Populations evolve over time 1. Read through the characteristics of life on this page. These 8 characteristics are what tell biologists if something is living or non-living. Remember, biology literally means “Study of life”. 1 2 2. Look at the images below. Each one is related to a characteristic of life. Some images may be related to more than one characteristic of life. See if you can match at least one characteristic of life to each image: A.____________________ C. ____________________ D. ____________________ B. ______________________________ E.____________________ F.______________________ H.________________________ G._________________________ I.___________________________ 2 3 Structure and Function: Structure and function is a central theme to the study of biology. Each major group of organisms has evolved its own particular body part “tool kit” – a collection of structures that have evolved in ways that make particular functions possible. From capturing food to digesting it, and from reproducing to breathing, organisms use structures that have evolved into different forms as species have adapted to life in different environments. The structure of wings, for example enable birds and insects to fly. The structures of legs enable horses to gallop and kangaroos to hop. Examine the figure below that shows carnivore and herbivore skulls. Don’t forget to read the captions! Now, since you’ve got some specific ideas about what structure and function are all about answer the questions below: 1. Think about your own teeth. What kinds of foods do you think human teeth are suited for? 2. List at least three ways the structure of human teeth serve the function of eating meat and plant material. a. ____________________________________ b. ____________________________________ c. ____________________________________ 3. Now, last but not least apply the theme of structure and function to something you’re very familiar with - your hands. List out all the ways you can think of that the structure of your hands serve the function of your hands. Hint – you are a primate! 3 4 Levels of Organization The specialized cells of multicellular organisms are organized into an organ system, as shown above. A tissue is a group of similar cells that perform a particular function. Many tissues work together as an organ to complete complicated tasks. A group of organs that work together to perform a specific function is called an organ system. 3. The Venn diagram to the right consists of four concentric circles. Complete the diagram to show the relationships among four levels of organization of life. Use the terms cells, organ, organ system, and tissue. 4. See if you can include the level of organization called “organism” in the Venn diagram. Show where it would be added. The diagram to the left shows a few of the different types of cells found in your body. Luckily, the cells in our body are specialized. Some cells are specialized to move, to react to the environment; still others to produce substance that the organism needs. Each of these specialized cells contributes to homeostasis in the organism. Describe how cells of a multicellular organism are like a baseball team, or choose any type of team you like. _________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ 4 5 Chemistry of water: Life is connected to water. Nearly 75% of our earth is covered in water. Why is it so special and vital to living things? Let’s look at the chemistry of water. Notice in the diagram to the right that water is composed of two hydrogen atoms and one oxygen (H2O). The diagram shows that one side of the water molecule is positively charged and the other is negatively charged. These opposite charges make water a polar molecule. The negative oxygen of one water molecule is attracted to the positive hydrogen of another molecule forming a hydrogen bond. In other words water likes to stick to itself. Water sticking to water is called cohesion. Water sticking to something else is called adhesion. 5. In the diagram to the right use dotted lines to draw in the bonds that form between water molecules. 6. What is the name of this type of bond? 7. What special property do the bonds give to water. It turns out that hydrogen bonds are important for a few more reasons. Hydrogen bonds give water a high specific heat and also cause water to expand upon freezing. Specific heat is the amount of energy required to raise one gram of water 1 degree Celsius. 8. Can you think of a reason why water can absorb so much heat? Hint – think bonds It turns out that water expands when frozen and actually becomes less dense than when in the liquid state. We call this frozen water ice, which we know floats. 9. Challenge yourself to think of two ways that specific heat and the freezing point of water help support life on earth. 5 6 Scientific Method/Scientific Terms: The scenes below show the steps involved in the scientific method read through the experimental scenario and answer the questions below. 10. Based on the scenario what is the difference between a hypothesis and an inference? 11. How did the control group differ from the experimental group? 12. What were the dependent and independent variables? 13. What was the observation that started the research? 6 7 In science the word theory applies to a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations A hypothesis is a scientific explanation for a set of observations that can be tested in ways that support or reject it. Identify whether each statement is a hypothesis or a theory. For a hypothesis, write an “H” on the line. For a theory, write a “T.” 14. The rate that grass grows is related to the amount of light it receives. 15. All life is related and descended from a common ancestor. 16. The universe began about 15 billion years ago. 17. New tennis balls bounce higher than old tennis balls. 18. Caffeine raises blood pressure. 19. Someone might argue against evolution and say that it’s “just a theory”. Why is this not a very good argument? Practice Questions: 1. Which characteristic is shared by all prokaryotes and eukaryotes? a. ability to store hereditary information b. use of organelles to control cell processes c. use of cellular respiration for energy release d. ability to move in response to environmental stimuli 2. Living organisms can be classified as prokaryotes or eukaryotes. Which two structures are common to both prokaryotic and eukaryotic cells? a. cell wall and nucleus b. cell wall and chloroplast c. plasma membrane and nucleus d. plasma membrane and cytoplasm 3. Alveoli are microscopic air sacs in the lungs of mammals. Which statement best describes how the structure of the alveoli allows the lungs to function properly? a. They increase the amount of energy transferred from the lungs to the blood. b. They increase the flexibility of the lungs as they expand during inhalation. c. They increase the volume of the lungs, allowing more oxygen to be inhaled. d. They increase the surface area of the lungs, allowing efficient gas exchange. 4. Which example is an activity that a fish most likely uses to maintain homeostasis within its body? a. using camouflage to avoid predators b. feeding at night to regulate body temperature c. moving to deeper water to regulate metabolic wastes d. exchanging gases through its gills to regulate oxygen levels 7 8 5. Which statement best describes an effect of the low density of frozen water in a lake? a. When water freezes, it contracts, decreasing the water level in a lake. b. Water in a lake freezes from the bottom up, killing most aquatic organisms. c. When water in a lake freezes, it floats, providing insulation for organisms below. d. Water removes thermal energy from the land around a lake, causing the lake to freeze. 6. Which diagram best represents the relationship of the items in the list below? 1. 2. 3. 4. 5. 6. cell organ organelle organ system tissue whole organism A. B. C. D. W. X. Y. Z. X Y Z W 7. Which property of water molecules explains the other properties listed below? a. Adhesion b. Cohesion c. Hydrogen bond d. Polar covalent bond 8. One property of water that makes it unique is its density. Which example describes a result of this property? a. Polar bears float on ice floes to hunt for food b. Trees transport water from their roots to their leaves c. Water strider insects walk on the surface of pond water d. Plants receive enough light to grow under the surface of a lake Use the picture below to answer question 9. 9. The picture shows a water droplets hanging on the tip of a pine needle. How do the physical properties of water result in the image shown? a. Cohesion allows droplets to form, and adhesion keeps the droplet on the needle. b. Adhesion allows droplets to form, and cohesion keeps the droplet on the needle. c. Cohesion allows droplets to form, and capillary action keeps the droplet on the needle. d. Adhesion allows droplets to form, and capillary action keeps the droplet on the needle. 8 9 10. Many trees in temperate environments have broad, flat leaves. How does this leaf structure support the function of obtaining energy? a. A flatter surface allows more oxygen to enter the leaf b. A flatter surface allows more water to be retained in the leaf during periods of dryness. c. A larger surface area allows more light to reach the mesophyll where photosynthetic cells are located. d. A larger surface area allows more room for photosynthetic cells. Open-ended question: 11. The diagram shows a single-celled freshwater protist. The contractile vacuole pumps water out of the cell. Part A: Describe how the function of the contractile vacuole helps the protist stay alive. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part B: Describe how the same function is carried out in animals. Identify at least one organ or system involved in this function. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part C: Describe how the same (or a similar) function is carried out in plants. Identify at least one organ, structure, or cell type involved in this function. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ __________________________________________________________________________________________ 9 10 Organic Chemistry Vocabulary Adhesion Cohesion Atom Concentration Biological macromolecules monomer Freezing point carbohydrate amino acid protein Macromolecule lipid nucleic acid enzyme catalyst pH molecule specific heat organic molecule Concepts to Know 1st Idea: Due to its properties, carbon is uniquely suited to form biological macromolecules. Use the diagrams below to fill in the blanks and describe why carbon is so important to life. Figure 2: Covalent Bonding between Carbon and Hydrogen Figure 1: Carbon Atom • Carbon has ______________ in the outer (valence) shell o Valence shell enables easy formation of four covalent bonds o Covalent bonds involve _____________ of ________________ between two atoms Carbon has the ability to form long chains by forming several carbon to carbon bonds in a row. The diagram to the left depicts two fatty acids. What is different about the structure of each? ____________________________________ ____________________________________ ____________________________________ Figure 3: Long Chain Carbon Compounds 10 11 Use the diagrams to fill in the blanks and describe how the variety of organic compounds can be explained by carbon’s properties. • • • • Organic compounds – Contain carbon atoms bonded to ________________. Variety is created when carbon bonds to other atoms. Covalent bonds between carbon atoms can be single, double or ________ bonded Carbon’s unique structure allows the formation of ________________________ (large molecules) 2nd Idea: Biological macromolecules form from monomers. Use the diagrams to fill in the blanks and describe how carbon allows for the formation of macromolecules. o Macromolecules are very large molecules o Most macromolecules are polymers o ________________ are long chains of bonded groups o ________________ are the molecules that link to form polymers o Dehydration Synthesis involves the removal of a water molecule and and is a common way for polymers to form. o Carbohydrate polymers found in plants that comprise the cell wall or serves as a means to store sugar are _________________ and _______________, respectively. o A carbohydrate polymer found in animals called _______________ stores glucose in the liver. o Hydrolysis is the process of adding water (H2O) breaking apart ___________________ 11 12 MACROMOLECULES: STRUCTURE AND FUNCTION Carbohydrates are broken down through hydrolysis to serve as fuel for the body or a source of carbon • Saccharide means sugar Carbohydrates can be ________________ (1 sugar) _______________, (2 sugars), or _______________ (more than 2 sugars) • • • _______________ breaks down carbohydrates like glucose for use in cellular respiration Cellular respiration is the process through which the body generates energy, or ________ Starch and cellulose are polysaccharides comprised of long chains of ___________. Lipids are nonpolar macromolecules made from long carbon chains • • • • • • • Lipids can be fats, oils, phospholipids, waxes, or steroids Fats store large amounts of energy ________________ compose cell membranes Steroids are made of four connected carbon rings with functional groups attached Lipids can be saturated or ______________ Saturated lipids have a ____________ shape and only single bonds between carbons, while unsaturated lipids have a nonlinear shape and have ___________ or triple bonds Fats and oils have a basic structure that consists of one _______________ connected to three _______________________. 12 13 Proteins are amino acid polymers that are essential to life • • • • • Amino acids have ___________ and _____________________ groups. They are made unique by the “R” group that is attached to carbon “R” is like a variable in algebra class. It can have many values (structures). The Function of the amino acid is determined by the structure and conformation of the “R” group Proteins are based on the different arrangement of 20 amino acid monomers. The unique __________ of a protein is vital to its ______________. Le Me As Val Ala Val Il Arg Cy Lys Val Al Hi ValPhe Gly Glu Ser Lys Val Thr Gly Le As Ala Val ArgGly SerPro Pro Amino Groove Nucleic acids (DNA and RNA) are polymers made from nucleotides • • • • • Nucleotides are monomers that consist of pentose (the pentagon shape in the diagram) attached to a phosphate group and nitrogenous base Pentose can be deoxyribose (as in DNA or deoxyribose nucleic acid) or ribose (as in RNA or ___________nucleic acid) DNA and RNA are central to heredity/genetics and are made unique by the nitrogenous ____________ that are attached Nitogenous bases can be cytosine (C), thymine (T), uracil (U), adenine (A), or guanine (G) DNA based codes are actually ________ or segments of DNA that code for a particular ___________. 13 14 Class Carbohydrates Lipids Proteins Nucleic acids Macromolecules and Their Function Monomers Functions Monosaccharides Energy, raw materials, energy storage, structural compounds Glycerol, fatty Energy storage, membranes, steroids, hormones, acids, steroids waterproof coverings, oils, waxes Amino acids Enzymes, membrane transport, movement, receptors, immune defense, structure (muscle, bone) Nucleotides Heredity, DNA and RNA code for amino acid sequence of proteins 3rd Idea: Enzymes are mostly macromolecule proteins that act as biological catalysts • • • • Catalysts increase the rate of a reaction without being changed by the reaction, catalysts lower the activation required for the reaction to proceed. Substrates are the reactants on which enzymes (catalysts) work Rate of reaction in both directions is increased by the presence of specific enzymes. ____________ _________ refers to the part of an enzyme that interacts with a substrate The rate of a reaction involving enzymes has to speed up at times and slow down at other times based on the needs of the organism (to maintain homeostasis). Use the video called Bozeman Science Enzymes to answer the questions • The process of turning enzymes on occurs through ______________ or ______________ o ______________ means the body only produces the enzyme when it is needed • Deactivation of enzymes occurs through _____________ or ______________ inhibition o Competitive inhibition means another chemical bonds with and ____________ the active site of the enzyme o ______________ inhibition means another chemical bonds to the enzyme in a position away from the active site, but blocks or alters the active site as a result 14 15 th 4 Idea: Enzyme reaction rates are impacted by temperature, pH & substrate concentration Enzyme Denatures (loses its shape and no longer functions) • Temperature is a measure of kinetic energy o Kinetic energy is the energy of motion. Higher temperature means ___________ moving particles. o The number of collisions between enzymes and substrates is increased if the particles move around ____________ (higher temperature) o Enzymes do not function well above or below the _____________ temperature o The enzyme denatures, or breaks down, if the enzyme gets too ______________ • pH measures acidity o Enzymes function best at the ______________ pH level o If the conditions are too acidic (low pH) or too basic (high pH), the enzyme may denature • Concentration is a measure of how many substrate molecules are present in a given volume. o _____________ ____ _______________ is the concentration where the reaction rate is maximized, the active sites of the enzymes are all used adding more substrate does not increase the rate of reaction. Practice Questions: 1. Which statement correctly describes how carbon’s ability to form four bonds makes it uniquely suited to form macromolecules? A. It forms short, simple carbon chains. B. It forms large, complex, diverse molecules. C. It forms covalent bonds with other carbon atoms. D. It forms covalent bonds that can exist in a single plane. 15 16 Use the diagram below to answer the question. Chemical Reaction HO 1 HO 2 1 3 2 3 H + HO 4 4 H + H 2O H 2. The diagram shows a reaction that forms a polymer from two monomers. What is this type of reaction called? A. glycolysis B. hydrolysis C. photosynthesis D. dehydration synthesis 3. Carbohydrates and proteins are two types of macromolecules. Which functional characteristic of proteins distinguishes them from carbohydrates? A. large amount of stored information B. ability to catalyze biochemical reactions C. efficient storage of usable chemical energy D. tendency to make cell membranes hydrophobic 4. Substance A is converted to substance B in a metabolic reaction. Which statement best describes the role of an enzyme during this reaction? A. It adjusts the pH of the reaction medium. B. It provides energy to carry out the reaction. C. It dissolves substance A in the reaction medium. D. It speeds up the reaction without being consumed. 5. A scientist observes that, when the pH of the environment surrounding an enzyme is changed, the rate the enzyme catalyzes a reaction greatly decreases. Which statement best describes how a change in pH can affect an enzyme? A. A pH change can cause the enzyme to change its shape. B. A pH change can remove energy necessary to activate an enzyme. C. A pH change can add new molecules to the structure of the enzyme. D. A pH change can cause an enzyme to react with a different substrate. 6. Whenever biological organic compounds, such as proteins and carbohydrates, are broken down or synthesized... a. a phase change of matter results. b. thermal expansion occurs. c. sunlight is required. d. energy is absorbed or released. 7. Why does an enzyme function as a catalyst in a reaction? a. It creates the right pH needed for the reaction. b. It decreases the amount of energy needed for the reaction. c. It provides the extra energy needed for the reaction. d. It maintains the proper temperature needed for the reaction. 16 17 8. A single atom of carbon is joined to a hydrogen atom. What is the maximum number of double bonds the carbon atom may yet form? a. 1 b. 2 c. 3 d. 4 9. Which of the following types of compounds is unlike the other three? a. wax . b. saturated fat c. phospholipid d. polysaccharide 10. Which of the following is not created as a result of dehydration synthesis? a. cellulose b. disaccharide c. glucose d. water 11. Which pair of terms is not correctly matched? a. Deoxyribose: RNA. b. Polypeptide: protein. c. Nitrogenous base; DNA. d. Amino acid: polypeptide. 12. Which does not describe a function of proteins? a. They encode genetic information b. They allow muscle cells to contract. c. They help to carry out chemical reactions. d. They make up structures that support the cell. Examine the structural formula below. 13. Which of the following biomolecules is best represented by this formula? a. nucleic acid b. protein c. carbohydrate d. lipid 17 18 14. The enzyme lactase catalyzes the breakdown of lactose (milk sugar) to glucose and galactose. Students set up a beaker with milk and lactase enzyme. Which describes how the concentrations of these substances will change? a. b. c. d. The concentration of lactase will decrease, and the concentration of galactose will increase. The concentration of galactose will decrease, and the concentration of glucose will increase The concentration of galactose will increase, and the concentration of lactase will remain the same. The concentration of lactose will increase, and the concentration of glucose will remain that same. 15. Organisms produce hydrogen peroxide (H2O2), a by-product of metabolism that is toxic to cells. The catalase protein catalyzes the reaction shown below. 2H2O2 → 2H2O + O2 Which statement describes the reaction? a. Water is the substrate. b. Hydrogen peroxide is the enzyme. c. Catalase is consumed by the reaction. d. Oxygen gas is a product of the reaction. 16. A reaction tube is set up at 37°C with twice as much substrate as enzyme. The pH level of the solution is 5. The reaction rate is measured. Which of the following changes will not affect the rate of the reaction? a. Increasing the pH level. b. Increasing the temperature. c. Increasing the enzyme concentration. d. Increasing the substrate concentration. Open-ended Question: 17. The graph shows the rate of enzyme activity in relation to pH for two enzymes – pepsin and pancreatic trypsin. Both enzymes break down proteins in food. Pepsin works within the stomach. Trypsin works in the small intestine. Part A: What does the graph indicate about the pH of the stomach and small intestine? ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part B: The contents of the stomach are released into the small intestine. How does this affect the function of the pepsin that is included with the stomach contents? ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ __________________________________________________________________________________________ Part C: What is the advantage to having two different protein-digesting enzymes, rather than just one? ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ 18 19 Cells and Cell Transport Vocabulary cell tissue cell membrane (plasma membrane) nucleus ribosome mitochondrion chloroplast protein synthesis active transport carrier (transport) proteins concentration gradient diffusion endocytosis endoplasmic reticulum endosymbiosis exocytosis facilitated diffusion extracellular golgi apparatus impermeable intracellular organelle osmosis passive transport plastids pumps (ion or molecular) unicellular multicellular What is the Cell Theory? a. All living things are made of cells. b. Cells are the basic units of structure and function in living things. c. New cells are produced from existing cells. Differences between Prokaryotic vs Eukaryotic Cells 1. Prokaryotic Cells: Single-celled organisms that lack internal membrane Bound compartments (Genetic material (DNA) is in a circular molecule) (simple) i.e. bacteria. -Hypothesized that the first type of cells on earth were prokaryotic 2. Eukaryotic Cells: Cells with membrane bound organelles such as, the nucleus. (more complex) i.e. animal and plant and animal cells) Eukaryotic Prokaryotic 3. Complete the Venn Diagram comparing prokaryotic and eukaryotic cells. Prokaryotic Eukaryotic 19 20 Directions: Write a P if the statement refers to Prokaryotes and an E if the statement refers to Eukaryotes, if the statement refers to both Prokaryotes and Eukaryotes write a B on the line. ___ 1. This type of cell does not have membrane bound organelles. ___ 2. This type of cell contains DNA. ___ 3. This type of cell contains organelles. ___ 4. A bacterium is an example of this type of cell. ___ 5. This type of cell contains a nucleus. Cell Structures & Functions All cells are enclosed by a cell membrane (plasma membrane). Within the membrane is the nucleus and the cytoplasm. Within the cytoplasm are organized structures that perform specific functions. These structures are called organelles. Please Note: The letters next to the structure of the cell indicates where the structure if found A =animal cells P = plant cells. AP = both plant and animal (A, P) Cell Membrane- surrounds the cell. It plays an active role in determining which substances enter and exit the cell. Some substances can pass freely through the cell membrane and others cannot, the membrane is said to be selectively permeable, or semipermeable. The cell membrane is composed primarily of lipids (phospholipids), proteins, and carbohydrates. (A, P) Nucleus- control center for all cell functions. Within the nucleus are chromosomes and at least one nucleolus. The nucleolus is a site of rRNA synthesis, and is responsible for the production of ribosomes. (A, P) Cytoplasm- the material in the cell outside the nucleus. It consists mainly of water. Within the cytoplasm are the various organelles of the cell. The cytoplasm provides the environment in which the organelles carry on the life processes of the cell. (A, P) Mitochondria- are found in the cytoplasm. Most stages of cellular respiration occur in the mitochondria. The energy released during respiration is stored in the form of high-energy chemical bonds in molecules of ATP. (P)Chloroplasts (also called plastids)-contain green pigment called chlorophyll, which carries on the process of photosynthesis. Mitochondria & Chloroplast-Developed from prokaryotic cells? WHAT?!?! Check out this really good explanation…relating to endosymbiotic theory http://www.youtube.com/watch?v=fAjev01mDZM Related questions: 1. Why are mitochondria and chloroplasts unique? 2. What are two characteristics about mitochondria and chloroplast that make them similar to prokaryotic bacteria cells? In other words, what evidence do scientists cite that supports endosymbiotic theory? 20 21 (A, P) Ribosomes- are small, dense granules (look like tiny circles on the diagrams) found free in the cytoplasm and on the rough endoplasmic reticulum. Ribosomes are composed mainly of RNA (rRNA). They are the centers of protein synthesis in the cell and consists of large and small subunits that join with mRNA and tRNA to make proteins from directions provided by __________ (a molecule contained in the nucleus) . (A, P) Endoplasmic reticulum-is a membrane-bound system of channels or tubes through which materials are transported within the cell. The membranes of the ER may also serve as sites of biochemical reactions. There are two types smooth and rough. The rough appearance is due to the presence of ribosomes on the membrane. Rough ER is found mainly in cells involved in protein synthesis. Smooth ER which has no ribosomes, is found mainly in cells involved in synthesis of nonprotein substances. The ER forms vesicles for transport of proteins to other areas within the cell or to the golgi apparatus. (A, P) Golgi Apparatus- is made up of a series of membrane-enclosed sacs, and it is usually found near the nucleus. This organelle is associated with the production of lysosomes and with the sorting and packaging of various cellular products. Produces transport vesicles (packages that move material inside or export material outside the cell) EXAMINE THE DIAGRAM BELOW, EXPLAIN THE PATH A NEWLY FORMED POLYPEPTIDE LEAVING A RIBOSOME MAY TAKE AS IT IS MODIFIED OR PACKAGED BEFORE USE WITHIN THE CELL OR OUTSIDE THE CELL: ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ _______________________________________ (A) Lysosomes- are “packages” or sacs, of digestive enzymes. They keep the enzymes separated from the rest of the cell contents until they are needed. (A, P) Vacuoles: are membrane-enclosed structures that are generally filled with water containing various dissolved substances. Vacuoles in animal cells are usually small, and vacuoles in plants are usually large. The pressure created by large water-filled vacuoles pushing against cell walls in plant cells helps to maintain the rigid structure of the plant. (A) Centrioles-are small organelles found just outside the nucleus in animal cells. Centrioles, assist with separating chromosomes during animal cell division. centrioles 21 22 (P) Cell Wall- structure found outside the cell membrane of plant cells. The cell wall is made up mostly of cellulose (polysaccharide), and it provides support for the cell. (A, P)Cytoskeleton- is a filamentous network of proteins that are associated with the processes that maintain and change cell shape and produce cell movements in animal and bacteria cells. In plants, it is responsible for maintaining structures within the plant cell, rather than whole cell movement. The main types of filaments the make up the cytoskeleton are Microfilaments (threadlike proteins) and Microtubules (tubes made of protein). 3. Use the following structure letters to label the structures indicated in the eukaryotic plant and animal cells. A. Cell membrane B. Nucleus C. Nucleolus D. Chromosome E. Cell Wall AB. Centriole AC. Mitochondria AD. Lysosome AE. Endoplasmic reticulum BC. Golgi Apparatus BD. Vacuole BE. Chloroplast Plant Cell Animal Cell 4. Fill in the names of the structures whose functions are listed below. Use the list of structures above for help. Structure Function Cellular Respiration Protein Synthesis Contains the hereditary information Storage of water, undigested food, and/or waste Active in movement of the chromosomes during cell division Storage of digestive enzymes Transport within the cytoplasm Packages secretions Phospholipid bilayer: The cell membrane is made of a lipid bilayer (two layers of phospholipids). Phospholipids have two parts, a polar head and a non-polar tail. Phospholipids are arranged with tails facing the interior of the membrane and polar heads facing out. The bilayer is flexible and if disturbed will reorient itself given the polar nature of the phospholipids. Watch this animation on the bilayer to see it in action. Cell membrane model (fluid mosaic) 22 23 Cellular Transport The cell membrane is semipermeable, some substances can pass through it freely, while others cannot. The movement of substances that can pass freely through the membrane depends on the concentration gradient of the substance, size of the substance and polarity of the substance. A. Passive Transport – Does not use energy – Moves from a high concentration to a low concentration Examples: • Diffusion: The movement of particles from regions of higher concentration to regions of lower concentration • Facilitated Diffusion: Transport proteins help ions and polar molecules diffuse through the membrane • Osmosis: The diffusion of water across a selectively permeable membrane. Osmotic conditions: Isotonic – concentration of solute is the same on both sides of the membrane (equilibrium) Hypertonic – the solution with a greater concentration of solute Hypotonic – the solution with the lesser concentration of solute Types of Solutions Cell stays same Cell shrinks B. Active Transport – Requires energy (usually energy used is from ATP) – Moves from a low concentration to a high concentration Examples: • Protein Pumps: an integral protein that transports ions and small molecules against their concentration gradients (ex. sodium potassium ion pump) • Endocytosis: The movement of a large substance into a cell by means of a vesicle • Exocytosis: The movement of material out of a cell by means of a vesicle 6. Circle the diagram letter that shows Endocytosis? A or B A 7. Circle the diagram letter that shows Exocytosis? A or B Sodium-potassium pump: One of the most important carrier proteins in animal cells. In nerve cells the pump is used to generate gradients of both sodium and potassium ions. These gradients are used to propagate electrical signals that travel along 23 nerves. B 24 Watch this cool animation on the sodium-potassium pump, and take the quiz! Record your answers to the questions below as you take the quiz. http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter38/sodiumpotassium_exchange_pump.html 1. ____ 2. ____ 3. ____ 4. ____ 5. ____ More Questions! 8. What is passive transport? 9. The paramecium is a fresh water protozoan. The salt content of its cytoplasm is greater than that of the surrounding medium. a. Does water tend to enter or leave the paramecium? Is this process passive or active transport? b. How does the paramecium expel water? Is this process passive or active transport? Explain. 10. Where does the energy for active transport come from and why is energy required for active transport? Practice Questions: 1. Using a microscope, a student observes a small, green organelle in a plant cell. Which energy transformation most likely occurs first within the observed organelle? a. ATP to light b. light to chemical c. heat to electrical d. chemical to chemical 2. Carbon dioxide and oxygen are molecules that can move freely across a plasma membrane. What determines the direction that carbon dioxide and oxygen molecules move? a. orientation of cholesterol in the plasma membrane b. concentration gradient across the plasma membrane c. configuration of phospholipids in the plasma membrane d. location of receptors on the surface of the plasma membrane 3. A sodium-potassium pump within a cell membrane requires energy to move sodium and potassium ions into or out of a cell. The movement of glucose into or out of a cell does not require energy. Which statement best describes the movement of these materials across a cell membrane? a. Sodium and potassium ions move by active transport, and glucose moves by osmosis. b. Sodium and potassium ions move by active transport, and glucose moves by facilitated diffusion. c. Sodium and potassium ions move by facilitated diffusion, and glucose moves by osmosis. d. Sodium and potassium ions move by facilitated diffusion, and glucose moves by active transport. 24 25 4. The rough endoplasmic reticulum and Golgi apparatus work together in eukaryotic cells. What is one way that the rough endoplasmic reticulum assists the Golgi apparatus? a. It assembles nucleic acids from monomers. b. It breaks down old, damaged macromolecules. c. It packages new protein molecules into vesicles. d. It determines which protein molecules to synthesize. In many eukaryotic cells, DNA stored in the nucleus is transcribed into messenger RNA. The mRNA is then transported into the cytoplasm where ribosomes assist in their translation into proteins. Finally, these proteins are packaged and sorted in the Golgi apparatus for use in other parts of the cell or in preparation for secretion into other cells. 5. Which of the following statements is supported by this description? a. Various organelles within a cell interact with each other to carry out life processes. b. Organelles within a cell act independently of each other at all times. c. Some organelles are more important than other organelles within a cell. d. Only up to three organelles may interact with each other at any given moment in time. 6. The cell membrane serves many functions. One of the cell membrane's functions is to help the cell maintain homeostasis. Which of the following statements best supports this claim? a. The cell membrane contains a polar region and a nonpolar region. b. The cell membrane contains proteins. c. The cell membrane contains phospholipids. d. The cell membrane regulates what goes in and out of the cell. In order for nerve cells and muscle cells to function properly, they require a high concentration of potassium ions inside the cells and a high concentration of sodium ions outside the cells. To maintain this condition, cells utilize sodium-potassium pumps embedded within their cellular membranes to move the ions against their concentration gradients. 7. Since sodium-potassium pumps require an input of energy to operate, they are an example of... a. passive transport. b. facilitated diffusion. c. filtration. d. active transport. 25 26 8. Most organisms can be divided into two categories - prokaryotes and eukaryotes. What is the main difference between these two categories? a. Eukaryotes are living organisms whereas prokaryotes include some nonliving matter. b. Prokaryotes do not possess any means of locomotion and are thus unable to move. c. Prokaryotes do not possess a nucleus or any other membrane-bound organelles. d. Eukaryotes are found in all of the six major taxonomic kingdoms. When a person inhales, oxygen fills tiny air sacs in the person's lungs. Next, the oxygen moves from these air sacs into small blood vessels that line the lungs, and then it moves into the bloodstream so that it can be transported around the body. Oxygen moves by random molecular motion from the air sacs of the lungs to the blood vessels because the concentration of oxygen in the air sacs is higher than the concentration of oxygen in the blood vessels. 9. This movement of oxygen molecules from an area of higher concentration to an area of lower concentration is known as _______. a. diffusion b. osmosis c. respiration d. photosynthesis 10. Energy conversion within an animal cell would be severely limited by removal of the cell's a. lysosomes. b. plastids. c. chloroplasts. d. mitochondria. 11. Which do the cells of an E. coli bacterium and an elephant have in common? a. Ribosomes to assemble proteins b. Mitochondria to produce proteins c. Chloroplasts found around the vacuole d. Chromosomes located in the cytoplasm 12. A cell from which organism would most likely be the smallest? a. A sugar maple tree b. A five-spotted ladybug c. A Saccharomyces yeast d. A Lactobacillus bacterium 13. Which is not an example of passive transport? a. Carbon dioxide in a capillary crosses the alveoli membranes of the lungs. b. Oxygen dissolved in the blood crosses the phospholipid portion of the membrane of a red blood cell c. Glucose molecules are transported by a carrier protein until its concentration on both sides of the membrane is equal d. Sodium ions move through a protein channel until there is a higher concentration in extracellular fluid than the cytoplasm 14. What is one way that facilitated diffusion differs from simple diffusion? a. Facilitated diffusion requires energy input b. Facilitated diffusion requires membrane proteins c. Facilitated diffusion requires a concentration gradient d. Facilitated diffusion requires small, nonpolar molecules. 26 27 15. Which of the following is not involved in the transport of molecules by facilitated diffusion? a. ATP b. phospholipids c. protein channels d. concentration gradient Open-ended Question: 16. Materials in cells may be transported by passive or active processes, both of which may involve concentration gradients, the phospholipid bilayer, and membrane proteins. Part A: Compare the role of concentration gradients in passive and active transport. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part B: Compare the role of the phospholipid bilayer in passive and active transport. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part C: compare the role of membrane proteins in passive and active transport. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ 27 28 Energy Vocabulary photosynthesis cellular respiration electron transport chain fermentation thylakoid cristae matrix mitochondria anaerobic krebs cycle glycolysis stroma aerobic ATP Concepts to Know What Does Life Need? ENERGY!! It either supplies itself (AUTO-TROPH / self – feed) or it eats something (HETERO – TROPH / other – feed ) The Laws of Thermodynamics dictate that no energy can be created or destroyed, it can only change forms. Chemical bonds are literally energy. When you eat something, you get energy for movement or growth from the energy locked in the food’s bonds. The trick to life is how to store that energy until you need it. The short-term storage molecule that ALL life has evolved to use is adenosine triphosphate, or ATP. Catabolic Pathways break down molecules so that Anabolic Pathways build up molecules ATP IS THE GO BETWEEN Look at the figure to the right with the batteries and flashlights. What is this visual analogy trying to tell us about ATP? ___________________ _______________________ _______________________ How does a ADP become fully charged? ____________________________________ ____________________________________ 1st Idea: Cell Respiration • • • • • The major way organisms harness energy. Large food molecules are taken in and ultimately the monosaccharide GLUCOSE is digested to capture its energy C6H12O6 + 6O2 6CO2 + 6H20 + energy There are multiple steps to the breakdown of glucose so that not all of the energy is released at once The steps are different depending if oxygen (aerobic) is present or not (anaerobic) 28 29 • • • • Aerobic Respiration: glycolysis Krebs cycle electron transport chain (ETC) Anaerobic Respiration: glycolysis fermentation Glycolysis occurs in the cytoplasm for prokaryotes and eukaryotes The Krebs Cycle and ETC occur in the mitochondria of eukaryotes Label the diagram with the following terms: alchohol/lactic acid; Krebs Cycle, glucose, fermentation, glycolysis, ETC FYI: Details about the Steps of Cell Respiration It’s all about rearrangement Every line in the structure of glucose to the left is energy (a line = a bond) During glycolysis, glucose (6C) is broken in half so a little energy is released with that broken bond…it is put into making ADP into ATP • Whenever a bond breaks in this process, an electron and a hydrogen need to be accounted for. A molecule NAD+ picks them up to form NADH • This concept continues in the Kreb Cycle – which will eventually break all of the bonds of the original glucose molecule. The carbons will leave as CO2. The hydrogens and electrons were put into NADH. • The MOST important part of Cell Respiration is the electron transport chain. All of the NADH that was formed so far drops off the electrons and the hydrogens at the inner membrane of the mitochondria (for eukarytoes). This membrane has proteins in it that pass the electrons to each other. Electrons are a different form of energy and can power the protein channels to open (this is active transport). The point of the electron transport chain is to pump hydrogen Electron Transport Chain ions (also from the NADH) across the membrane into a tiny space. WHY? It seems silly, but almost all life does this process. By building a gradient of H+ ions in this tiny mitochondrial space, the H+ build up and need to diffuse out, through a special channel called ATP synthase (this is passive transport). This molecule literally spins as H+ goes through it and makes ATP from ADP. What about the oxygen? After passing the electron down the chain to make the gradient happen (which is known as chemiosmosis), the electron has to go somewhere. It would cause damage in your cell otherwise. Oxygen is there to pick it up and combine it with the hydrogens to make….WATER! • • • • • • 29 30 Aerobic cell respiration What do I need to know? The overall equation: ___________________________________________________________________________ What organisms undergo cellular respiration? ________________________________________________________ What are the 3 major steps of aerobic respiration? _____________________________________________________ What will happen when oxygen is not present? _______________________________________________________ What is the purpose of cellular respiration? ___________________________________________________________ Where does cellular respiration and fermentation occur with a eukaryotic cell? _______________________________ nd 2 Idea: Photosynthesis Where does the sugar come from in the first place that will get broken down in cellular respiration?!?! • Occurs in photosynthetic autotrophs (plants, algae, some bacteria); in the chloroplast of eukaryotes • Has 2 major steps: the light reaction and the Calvin cycle (light independent reaction) • The Light Reaction generates ATP and NADPH (an electron and hydrogen carrier) so that the Calvin Cycle can run • The Calvin Cycle is the part that makes the sugar. Carbon dioxide comes into a plant (via leaf stomata) and is joined together with other carbons in the cell to ultimately make glucose (6 carbons). Making bonds requires energy in this process, which is why ATP and some extra electrons and hydrogens are needed. • • 6CO2 + 6H20 + energy C6H12O6 + 6O2 The input of energy to start the light reaction is from sunlight! What you need to know: PLANTS PHOTOSYNTHESIZE AND DO CELL RESPIRATION!!!! They have chloroplasts AND mitochondria! Plants need mitochondria to generate ATP from sugars they have created through photosynthesis. Chloroplasts: contain chlorophyll and are found in leaves, they perform photosynthesis. Chlorophyll is a light capturing pigment. The light reaction mentioned above occurs in the thylakoids and the light independent reaction (Calvin cycle) Diagram of a Chloroplast occurs in the stroma of the chloroplast. 30 31 Major input and outputs of the process. Label the diagram below with the following: CO2, O2, Water, Glucose, sunlight Bonus: can you label where ATP/NADPH, ADP/NADP+, stroma, thylakoid, light reaction and Calvin Cycle would be? Photosynthesis Reminders WHAT Light-Dependent Reactions Light-Independent Reactions “The Light Reactions”’ “The Dark Reaction”/The Calvin Cycle WHAT photosynthetic reactions that requires light. produces sugars by using the energy from ATP & NADPH formed during light-dep rxn WHERE thylakoid (membrane & inside) WHERE in the stroma of the chloroplast “WHO” Photosystem II & Photosystem I “WHO” Rubisco; uses CO2 from outside & existing Various proteins embedded in the thylakoid membrane WHEN WHY carbon molecules in the cell (RuBP) WHEN when the sunlight shines WHY captures sunlight energy to produce ATP which will eventually be used to construct the doesn’t depend on sun plant needs to produce high-energy glucose molecules for growth glucose molecules. HOW HOW uses light & water to produce oxygen and converts ADP to ATP and NADP+ to NADPH uses the ATP & NADPH create the new bonds of glucose 31 32 Complimentary nature of photosynthesis and respiration: Light 6 CO2 + 6 Carbon H2O Water C6H12O6 + 6 O2 energy PHOTOSYNTHESIS Glucose Oxygen RESPIRATION: C6H12O6 + 6 Glucose 6 CO2 O2 + Carbon dioxide Oxygen 6 H2O Water + ATP Energy Key Connections • Photosynthesis and respiration are about energy transformations. Notice the complimentary nature of both equations above. How are they connected? _______________________________________________ • Photosynthesis captures energy from sunlight in the bonds of glucose, while respiration releases the energy from glucose in the form of ATP so cellular work can be completed. • Autotrophs are always the basis of the food chain. As a human you cannot make your own sugars! • The source of carbohydrates AND oxygen on the planet is photosynthesis COMPARISON QUESTIONS Answer P for Photosynthesis, CR for Cell Respiration, or B for both ______ Releases O2 ______ Releases CO2 ______ Uses CO2 ______ Creates ATP during the process ______ Produces sugar ______Uses sugar Answer A for Animals, P for Plants, or B for both ______ Releases O2 ______Releases CO2 ______ Uses CO2 ______ Creates energy in the form of ATP ______Produces sugar ______Uses sugar 32 33 Practice Questions Bioenergetics: 1. Photosynthesis and cellular respiration are two major processes of carbon cycling in living organisms. Which statement correctly describes one similarity between photosynthesis and cellular respiration? a. Both occur in animal and plant cells. b. Both include reactions that transform energy. c. Both convert light energy into chemical energy. d. Both synthesize organic molecules as end products. The energy for life comes primarily from the Sun. 2. What process provides a vital connection between the Sun and the energy needs of living systems? a. decomposition b. cellular respiration c. transpiration d. photosynthesis The processes of photosynthesis and cellular respiration form a continuous cycle. 3. During this cycle, the products from one process serve as the starting materials for the other. Which of the following materials correspond(s) to box number 3? a. sunlight b. carbon dioxide and water c. ATP (energy) and heat d. oxygen and glucose 33 34 4. A protein in a cell membrane changed its shape to move sodium and potassium ions against their concentration gradients. Which molecule was most likely used by the protein as an energy source? a. ATP b. ADP c. catalase d. amylase 5. Which pair of molecules are broken down by the cell to release energy? a. ADP and glucose b. ATP and glucose c. ATP and carbon dioxide d. ADP and carbon dioxide 6. Which pair of compounds are raw materials for cellular respiration? a. Glucose and ATP b. Oxygen and glucose c. Carbon dioxide and ATP d. Carbon dioxide and oxygen 7. Which does not take place in the mitochondria of the cell? a. Carbon dioxide is produced b. Hydrogen ions cross a membrane c. Glucose is broken down into organic compounds d. The ATP synthase enzyme combines ADP and phosphate 8. In which organism does respiration not take place in the mitochondria? a. bacteria b. maple tree c. seaweed d. yeast 9. Which comparison between ATP and ADP is correct? a. ATP stores less chemical energy than ADP and phosphate b. ATP stores more chemical energy than ADP and phosphate c. Less energy is used to form ATP than is released from ATP hydrolysis d. More energy is used to form ATP than is released from ATP hydrolysis 10. Which is a difference between photosynthesis and cellular respiration? a. Photosynthesis can produce glucose without oxygen b. Photosynthesis occurs only in plants, and respiration occurs only in animals c. Cellular respiration stores energy, but photosynthesis releases energy d. Cellular respiration releases oxygen, but photosynthesis releases carbon dioxide 11. Which statement describes what occurs in the stroma of the chloroplast? a. Oxygen is released b. Carbon dioxide reacts c. Water molecules are split d. Chlorophyll absorbs energy 34 35 12. Which pair of compounds are both products of photosynthesis? a. Water and glucose b. Oxygen and glucose c. Glucose and carbon dioxide d. Oxygen and carbon dioxide 13. Which of the following best explains the relationship between photosynthesis and cellular respiration? a. Both produce carbon dioxide and oxygen b. Both require energy from sunlight to occur c. The products of one are the reactants of the other d. A plant can carry out either one process or the other Open-ended Question: 14. The law of conservation of energy states that energy cannot be created or destroyed. It can only change in form and move from place to place. An ATP molecule in an animal cell is used for energy. Part A: Explain how the energy reached the ATP molecule from its original source. __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ _______________________________________________________________________________________________ Part B: Describe how energy changed in form from its original source to the ATP molecule. __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ Part C: Explain how the energy changes when the ATP molecule is converted to ADP and phosphate. __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ __________________________________________________________________________________________________ 35 36 Cell Reproduction & Genetics Vocabulary Allele Cell cycle Chromosomes Cloning Co-dominance Crossing over Cytokinesis DNA replication Dominant inheritance Gamete Gene Gene splicing Gene therapy Gene recombination Genetic engineering Genetics Incomplete dominance Inheritance Interphase Meiosis Mitosis Multiple alleles Nondisjunction Polygenic trait Recessive inheritance Semiconservative replication Sex-linked trait Genetically modified organism genotype phenotype Concepts to Know Main Concept #1: Describe the events that occur during the cell cycle: interphase, nuclear division (i.e. mitosis), cytokinesis. • The Cell cycle – period of time from the beginning of one cell division to the beginning of the next o During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells, each of which then begins the cell cycle again o Consists of 4 phases M phase – mitosis – the division of the cell nucleus and cytokinesis (includes PMAT) makes body cells G1 – intense growth and activity S phase – copying of chromosomes Interphase G2 – intense growth and activity • G stands for gap • Interphase – time between two cell divisions (cell spends the most time in this phase) o Interphase can be broken into 3 phases: G1, S, G2 G1 cells do most of their growing, increasing in size and synthesizing new proteins and organelles S DNA is replicated • Need to copy DNA so each new cell has a complete copy G2 usually shortest of 3 phases • Organelles and proteins required for cell division are produced • Cell enters M phase once complete MITOSIS 36 37 • Biologists divide the events of mitosis into 4 phases: prophase, metaphase, anaphase, and telophase 1. prophase – 1st and longest phase of mitosis (50-60% of total time) o chromosomes become visible o centrioles separate and take up positions on opposite sides of the nucleus focal point that helps organize spindle (fan-like microtubule structure that helps separate the chromosomes chromosomes attach to spindle at the centromere plants do not have centrioles • organize spindle from areas called centrosomes o nucleolus disappears o nuclear envelope breaks down 2. metaphase – 2nd phase of mitosis o chromosomes line up along center of the cell o microtubules connect the centromere of each chromosome to the poles of the spindle 3. anaphase – 3rd phase of mitosis o centromeres that join the sister chromatids split o chromatids separate and become individual chromosomes o chromatids get pulled apart, to the poles of the spindle o ends when they stop moving 4. telophase – 4th phase of mitosis o chromosomes become loose and begin to disperse o nuclear envelope reforms o spindle breaks apart o a nucleolus reappears o cytokinesis – division of the cytoplasm usually occurs at the same time as telophase in animals, cell membrane pinches in at the middle in plants, cell plate forms midway through the cell • beginning at the cell wall MEIOSIS 37 38 • • • • meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half and homologous chromosomes in a diploid cell are separated o involves two distinct stages: meiosis I and meiosis II o one diploid (full # of chromosomes) cell becomes 4 haploid (half # of chromosomes) cells homologous – two sets of chromosomes (one from mom and one from dad) o if a cell has both sets of chromosomes = diploid (2n) 2 complete sets of chromosomes with 2 complete sets of genes o gametes with only one set of chromosomes = haploid (n) contain only one set of genes meiosis I – prior to meiosis I, each chromosome is replicated o chromosomes line-up similar to mitosis, except the homologous chromosomes form a tetrad (4 chromatids) occurs during prophase I crossing over may occur – results in the exchange of alleles between homologous chromosomes and produces new combinations of alleles o homologous chromosomes separate and two new cells are formed meiosis II – cells from meiosis I enter meiosis II o cell does not undergo chromosome replication o anaphase II – chromatids separate instead of homologous pairs o Each resulting sex cell (gamete) has one copy of each gene Main Concept #2: Compare the processes of mitotic and meiotic nuclear division. In the table provided, place a check mark in the columns that apply to the particular event. If appropriate indicate whether it happens in prophase (P), metaphase (M), anaphase (A), or telophase (T) 38 39 Description / Event Interphase Mitosis Meiosis I Meiosis II Neither Nuclear membrane starts to break down Sex cells result Daughter cells are identical to parent Body cells result Homologous chromosomes line up in middle of cell Final chromosome # is the same as the parent cell Diploid cells result at end Homologous chromosomes assort independently Tetrads form DNA is replicated Chromosomes migrate to opposite poles Cytokinesis begins Cells are genetically different Spindle fibers form Haploid Cells Result Sister chromatids separate Crossing over happens Each cell contains only one copy of each gene • nondisjunction – failure of homologous chromosomes to separate during meiosis o if nondisjunction occurs, abnormal numbers of chromosomes may find their way into gametes, and a chromosome disorder may result (e.g. down syndrome, 3 chromosomes at 21st pair) Main Concept #3: Describe how the process of DNA replication results in the transmission and/or conservation of genetic information. 39 40 • DNA Replication – copying of DNA o Ensures that each resulting cell will have a complete set of DNA molecules o During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template against which the new strand is made called semiconservative replication Main Concept #4: Explain the functional relationships between DNA, genes, alleles, and chromosomes and their roles in inheritance. • Conclusions from Mendel’s experiments with pea plants 1. Inheritance is determined by “factors” that are passed from one generation to the next = genes o each gene controlled one trait with two contrasting characters o different forms of a gene = alleles 2. Principle of dominance – states that some alleles are dominant and others are recessive o organism with dominant allele for a particular form of a trait will always have that form (ex. T=tall) o organism with two recessive alleles for a particular form of a trait will have that form only (tt = short) 3. Segregation – separation of alleles a. During formation of gametes (sex cells) each allele is separated DNA is a molecule that carries genetic codes which determine the sequence of amino acids in proteins A gene is a specific segment of the DNA molecule that codes for a specific protein – EX: eye color An allele is a form of a gene – meaning that it will continue to do what is asked (make eye color) but it has different information – blue eyes, brown eyes, hazel eyes…) TT = alleles are alike A chromosome is a whole bunch of genes linked together into an organized structure (eukaryotes it is linear / prokaryotes it is circular) Tt = alleles are different Main Concept #5: Describe and/or predict observed patterns of inheritance (ie. dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles). 4. Probability – likelihood that a particular event will occur 40 41 5. 6. 7. 8. 9. 10. a. Probability of two events happening, you multiply the individual probabilities i. Past outcomes do not affect future ones b. The principles of probability can be used to predict the outcomes of genetic crosses Punnett square – diagram that helps determine gene combinations that might result from a genetic cross Capital letters represent dominant alleles; lower case letters represent lower case letters Homozygous – have two identical alleles – true-breeding Heterozygous – have two different alleles – hybrid – carrier Phenotype – physical feature (attached or detached earlobes) Gentoype – genetic make-up (EE or Ee or ee – represent genes) 11. for two genes, alleles segregate independently a. independent assortment – genes segregate independently and do not influence each other’s inheritance i. the principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes 12. some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes a. incomplete dominance (RedXWhite = pink) – one allele is not completely dominant over another i. heterozygous phenotype is somewhere between two homozygous phenotypes b. codominance (AB blood type, sickle cell) – both alleles contribute to the phenotype of the organism i. heterozygous phenotypes have some of both homozygous phenotypes c. multiple alleles (blood type – ABO) – genes that have more than 2 possible alleles d. sex linked traits (colorblindness, hemophilia) – traits from genes carried on X or Y chromosomes, genes on X usually occur at a higher rate in boys, females can be carriers and males cannot. e. polygenic traits (height, skin color, hair color) – traits that result from the interaction of many genes i. these traits are also greatly influenced by the environment Monohybrid Cross 1. Two fish meet at the coral reef, fall in love, and get married that same night. They decide to make babies right away. The mom fish has a big fluffy tail (TT) while the dad has a very boring flat tail (tt). The dad is worried that he will pass his ugly tail down to his kids. What is the chance that the first child will have a flat tail? T = fluffy tail t = flat tail Genotypic Ratio: ______________________________ Phenotypic Ratio: _________________________________ Incomplete Dominance: 1. In Japanese four-o’clocks, the gene for red flower color (R) is incompletely dominant over the white flower color(r). For each of the following situations, predict the genotypic and phenotypic ratios of a red plant crossed with a white plant. 41 42 Codominance 1. The palomino horse is a hybrid (mix) showing a golden coat with a lighter mane and tail. A pair of codominant alleles, D1 and D2 is known to be involved in this trait. Horses with the D1D1 genotype are chestnut colored, horses with the D1D2 genotype are palomino, and horses with the D2D2 genotype are white in color. A. Two palomino horses mate by artificial insemination. What types of offspring could be produced? Sex-Linked Traits 1. White eyed fruit flies are the result of a sex-linked recessive gene. Show the results from a cross between a redeyed (R) male and white-eyed (r) female fruit fly. Main Concept #6: Explain how genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy). 13. selective breeding – allowing only those animals with desired characteristics to produce the next generation a. humans use selective breeding to pass desired traits on to the next generation of organisms (pure bred dogs, domestic livestock, etc.) 14. genetic engineering – making changes in the DNA code of living organisms 15. Cutting / Splicing DNA (recombinant) a. Restriction enzymes – cuts DNA at a specific sequence of nucleotides b. cutting and pasting i. recombinant DNA – taking DNA and “pasting” it to another organism’s DNA (usually pasted into a plasmid from bacteria) Why would scientists want to recombine a human gene for growth hormone or insulin with a plasmid? What benefit is provided? _____________________________________________________ _____________________________________________________ 16. transgenic organisms /genetically modified organisms– organisms that contain genes from other organisms a. using the basic techniques of genetic engineering, a gene from one organism can be inserted into cells from another organism. These transformed cells can then be used to grow new organisms 17. clone –genetically identical organism or cells produced from a single cell 42 43 How could cloning help humans in need of organs? ________________________________________________________ 18. gene therapy is the process of attempting to cure genetic disorders by placing copies of healthy genes into cells that lack them 19. DNA fingerprinting – Cutting and separating DNA so repeats in the genetic code that are unique to individuals can be compared for the purpose of identification On the lines below, write T next to an example of a transgenic organism, and C next to an example of a clone. _____1. A goat that produces spider’s silk in its milk _____2. A plant that is grown from a cell into which Agrobacterium has incorporated recombinant DNA _____3. A lamb that is born with the same DNA as a donor cell _____4. A colony of bacteria that grows from one bacterium _____5. A bacterium that can produce human insulin Which two samples might be from a set of identical twins? __________________ Practice Questions: 43 44 1. Which statement best describes the phase of the cell cycle shown? A. The cell is in prophase of mitosis because the number of chromosomes has doubled. B. The cell is in prophase I of meiosis because the number of chromosomes has doubled. C. The cell is in telophase of mitosis because the cell is separating and contains two copies of each chromosome. D. The cell is in telophase of meiosis because the cell is separating and contains two copies of each chromosome. 2. Mitosis and meiosis are processes by which animal and plant cells divide. Which statement best describes a difference between mitosis and meiosis? A. Meiosis is a multi-step process. B. Mitosis occurs only in eukaryotic cells. C. Meiosis is used in the repair of an organism. D. Mitosis produces genetically identical daughter cells. Suppose that the central C-G base pair in the DNA molecule below is substituted by an A-T base pair. 3. What is the most likely result of this mutation? a. genetic variation b. genetic clones c. incomplete translation d. identical offspring 4. Hemophilia is an inheritable genetic disorder that prohibits the proper formation of blood clots. The recessive gene that causes hemophilia is located on the X-chromosome. Given this information, which of the following statements is true? a. In order for a male offspring to be a hemophiliac, his mother must be a hemophiliac. b. In order for a female offspring to be a hemophiliac, her father must be a hemophiliac. c. In order for a male offspring to be a hemophiliac, his father must be a hemophiliac. d. In order for a female offspring to be a hemophiliac, her mother must be a hemophiliac. 44 45 5. Which of the following statements is true? a. Mitosis results in the formation of two haploid gametes which can then combine to form a diploid daughter cell. b. During the process of meiosis, haploid cells are formed. After fertilization, the diploid number of chromosomes is restored. c. The process of meiosis forms daughter cells which are genetically identical to their parent cells. d. The daughter cells formed during mitosis are genetically similar to, though not identical to, their parent cell. 6. In a flowering plant species, red flower color is dominant over white flower color. What is the genotype of any redflowering plant resulting from this species? A. red and white alleles present on one chromosome B. red and white alleles present on two chromosomes C. a red allele present on both homologous chromosomes D. a red allele present on at least one of two homologous chromosomes 7. Which of the following best describes the way that genes, chromosomes, and DNA are related? a. Chromosomes contain several genes, which are made up of sequences of DNA. b. Genes contain several chromosomes, which are made up of sequences of DNA. c. Genes contain several sequences of DNA, which are made up of chromosomes. d. Sequences of DNA contain several genes, which are made up of chromosomes. 8. If a cat has 38 chromosomes in each of its body cells, how many chromosomes will be in each daughter cell after mitosis? a. 19 c. 11 b. 76 d. 38 9. Tom is going to buy two hamsters. He wants to breed them and sell the baby hamsters to a local pet store. The store owner tells him that his customers prefer dark brown hamsters with white bellies, long fur, black eyes, and long tails. Tom found a female hamster with all of those characteristics. Which male hamster should Tom buy in order to have the BEST chance of breeding baby hamsters with MOST of those characteristics? Hamster W Tan Fur Dark White Belly Long Fur Long Tail Brown Eyes Hamster X Brown Fur White Belly Long Fur Long Tail Brown Eyes a. W b. Z Hamster Y Tan Fur White Belly Short Fur Long Tail Black Eyes Hamster Z Dark Brown Fur Dark Brown Belly Long Fur Short Tail Black Eyes c. Y d. X Use the table below to answer the question. Blood Types 45 46 Genotypes ii A A A I I ,I i IBIB, IBi IAIB Phenotypes O A B AB 10. Blood type is inherited through multiple alleles, including IA, IB, and i. A child has type A blood. If the father has type AB blood, what are all the possible phenotypes of the mother? A. phenotypes O or A B. phenotypes A or AB C. phenotypes A, B, AB D. phenotypes O, A, B, AB 11. Genetic engineering has led to genetically modified plants that resist insect pests and bacterial and fungal infections. Which outcome would most likely be a reason why some scientists recommend caution in planting genetically modified plants? A. unplanned ecosystem interactions B. reduced pesticide and herbicide use C. improved agricultural yield and profit D. increased genetic variation and diversity 12. A cell in the process of cell division contains the normal chromosome number. Each chromosome consists of two identical sister chromatids. During which stages and processes can such a cell exist? A. telophase of mitosis, but no stage of meiosis B. metaphase of mitosis, but no stage of meiosis C. anaphase I of meiosis and anaphase of mitosis D. prophase I of meiosis and prophase of mitosis 13. Which statement correctly describes the alleles for any gene in a female cat’s body cell? A. they have the same DNA sequence, but are located on separate chromosomes B. They have different DNA sequences, but are located on the same chromosome C. They may have the same or different DNA sequences, but are located on the same chromosome D. They may have the same or different DNA sequences, but are located on separate chromosomes 14. A child has type O blood. If the child’s mother has type A blood, what are all the possible genotypes and phenotypes of the father? A. ii only B. ii and IAi C. ii, IAi, and IBi D. ii, IAi, IAIA, and IBi 15. The gene for seed shape in pea plants has two alleles, resulting in either smooth or wrinkled peas. A pea plant with one smooth allele and one wrinkled allele produces only smooth peas. Based on this information, which conclusion can be drawn? A. both alleles are codominant B. one allele is incompletely dominant C. the allele for smooth seeds is recessive D. the allele for wrinkled seeds is recessive 16. Fruit flies normally have red eyes. A recessive allele causes some fruit flies to have purple eyes. Which statement describes the purple-eyed offspring of a red-eyed parent and a purple-eyed parent? 46 47 A. The offspring has two recessive alleles located on the same chromosome B. The offspring has two chromosomes with a recessive allele present on each. C. The offspring has one dominant and one recessive allele located on the same chromosome D. The offspring has one chromosome with a dominant allele and one chromosome with a recessive allele. 17. A scientist uses enzymes to splice genetic DNA into a plasmid, and then inserts the plasmid into a cell. Which of the following is most likely an application of this process? A. producing an exact genetic clone of prized racehorse B. producing a vaccine against the human papillomavirus C. determining which of several rice varieties should be crossed D. determining whether a suspect’s blood was present at a crime scene 18. Which of the following is not an example of genetic engineering? A. An agricultural scientist creates a hybrid stain of rice by crossing two rice varieties. B. A biology student inserts plant DNA into bacteria to determine its role in the cell cycle. C. A vaccine manufacturer inserts a plasmid containing a gene forma a virus into yeast cells. D. A medical researcher isolates a functional copy of a muscular dystrophy gene for gene therapy. Open-ended Question: 19. A cattle farmer genetically crosses a cow (female) with a white coat with a bull (male) with a red coat. The resulting calf (offspring) is roan, which means there are red and white hairs intermixed in the coat of the calf. The genes for coat color in cattle are co-dominant. Part A: Although a farm has cattle in all three colors, the farmer prefers roan cattle over white or red cattle. Use the Punnett square to show a cross that would produce only roan offspring. Part B: Explain how a roan calf results from one white- and one red-coated parent. In your explanation, use letters to represent genes. Be sure to indicate what colors the letters represent. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part C: Predict the possible genotypes and phenotypes of the offspring produced from two roan cattle. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ 47 48 Protein Synthesis Vocabulary Transcription Translation Translocation Chromosomal mutation Deoxyribonucleic acid Frame-shift mutation Gene expression Mutation Point mutation Concepts to Know The Central Dogma: How our DNA code makes our Phenotype DNA RNA Protein How are we so different? Why are we not identical to a plant? Or a bacterium? Or each other? The DNA code is the same in all organisms but the sequence of the letters is different. All life uses A,C,T,G in double-stranded base pairs. This is the same concept that War and Peace is not identical to your IPod Warranty, but they’re still written in English. DNA is just a language. A very, very, very important language. This is why scientists can manipulate life in the laboratory so easily. This is also the key to understanding evolution from a single common ancestor. DNA is the code of life –DNA is letters; codons are words; proteins are messages that make sense. 1st Idea: Life Contains DNA: it is a SELF-REPLICATING molecule. 48 49 DNA replicates itself (via DNA polymerase and other enzymes) in a semi-conservative manner. This means that at the end of replication, each of the daughter molecules has one old strand, from the parent strand of DNA, and one strand that is newly synthesized. (see pic). Adenine pairs with Thymine (A = T) Guanine pairs with Cytosine (G = C) The bonds between the base pairs are hydrogen bonds If given the template strand of DNA below, what is the complementary sequence? 5’ A T G T A T G C C A A T G C A 3’ 3’__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ 5’ DNA STRUCTURE Nucleic Acid (polymer) is made of nucleotides (monomer) IDENTIFY EACH AS W, X, OR Z IN THE DIAGRAM A nucleotide is made of: a. a sugar _____, b. a phosphate group_____, c. and a nitrogenous base _____. I. DNA REPLICATION DNA polymerase is an enzyme (ends in –ase). All enzymes have a specific active site. The DNA in this example is the substrate and only can fit into the enzyme (DNA polymerase) a certain way. This is why DNA replication has a leading and a lagging strand when made. The enzyme can only fit onto DNA via the 3’ hydroxyl side, not the 5’ phosphate side. What letter in this diagram represents the continuous leading strand? ______ What letter represents the Okazaki fragments of the lagging strand? ______ II. PROKARYOTES VS EUKARYOTES Prokaryotes (“before nucleus”) evolved before eukaryotes (“true nucleus”) and have slight differences in their DNA structure. 2nd Idea: DNA is the source message but RNA is the working copy MAJOR DIFFERENCES BETWEEN DNA AND RNA 49 50 The DNA is like the encyclopedia you can never check out of the library. However, you are allowed to make copies of the information. That’s what RNA is – a copied message of the important pages. Making copies ensures that you don’t ‘ruin’ the original by taking it out of the nucleus (this only applies to eukaryotes), you can make copies in bulk, AND you only have to make copies of what you need. You wouldn’t copy all 6000 pages of an encyclopedia would you? No! Only the 4-5 pages you might need for a report. In eukaryotes, we only code for ~ 2% of our DNA! RNA (ribonucleic acid) is the intermediate between DNA and protein. It has slight differences to DNA. TRANSCRIPTION is the process of making RNA from DNA (via the enzyme RNA polymerase). This happens in the nucleus for eukaryotes, but would happen in cytoplasm for prokaryotes. Can you complete this message? T A C C C C T T T G G C A T A G A A U G G G __ __ __ __ __ __ __ __ __ __ __ __ Important Points about TRANSCRIPTION: DNA RNA Protein • A single-stranded copy of RNA is made of the DNA gene, where U is complementary to A instead of T. • Transcription occurs in nucleus for eukaryotes. • Eukaryotic mRNA has EXONS (expressed message) and INTRONS (in-between message) • Introns get spliced (cut out) of the mRNA to make the final mRNA. 3rd Idea: Translation is matching an amino acid to the mRNA in order to make the protein 50 51 Important points about TRANSLATION • The mRNA leaves the nucleus cytoplasm (in eukaryotes) • Message is read at the ribosome • mRNA is read 3 letters at a time • AUG is the start signal • 1 Codon (3 letter message) is translated into 1 amino acid • transferRNA molecule has one end (anticodon) that matches the mRNA . Each anticodon specifies an amino acid. • There are 20 amino acids • The amino acids are bonded together as peptide chains…which fold into proteins If an mRNA transcript has 300 nucleotides, how many amino acids would that code for? TRANSLATION : DNA RNA Protein Ex: the message AUGGGGCAAUAA codes for Met-Gly-Gln-* (the * tells the ribosome to stop) What does this message code for? AUG CUU CCA GAG UGA ____ _____ _____ _____ _____ • • • After a polypeptide chain is made from amino acids (at a ribosome), it might be used right away in the cytoplasm, or it might be sent to the ER or Golgi apparatus to have more folding or carbohydrates added. Proteins made on free ribosomes will work in the cytoplasm Proteins made on the rough ER will go to the cell membrane or be excreted 4TH Idea: Mutations in the DNA or RNA sequence produce the wrong amino 51 52 acid sequence. *****The ultimate source of evolution is mutation***** MUTATION : A change in DNA sequence • Point Mutations: Change one or two base pairs Insertion, Deletion, Substitution Deletion and insertion are “frameshift mutations” - that is, they change the codon reading frame. Other mutation vocabulary Silent Mutation - the mutation goes unnoticed – it does not change the amino acid sequence or is not in a coding region Missense – an insertion, deletion, or substitution that would make the message different Nonsense – really bad; a stop codon is created and the message stops prematurely Chromosomal Mutations Deletion: The loss of all or part of a chromosome Duplication: A segment is repeated Inversion: part of the chromosome is reverse from its usual direction. Translocation: one chromosome breaks off an attaches to another chromosome. Example: Remember that DNA and RNA are just a language. emphasize the point of mutation, I am using English (an with 26 letters, not 4!) Imagine you have the following message: THE CAT ATE THE RAT 52 To alphabet 53 Using the above bolded mutations, label the type of mutation each must be: _____________________ THE HAT ATE THE RAT _____________________ TTH EHA TAT ETH ERA T _____________________ THE ATA TET HER AT The “Central Dogma of Biology” is summarized as: _____________ _____________ Fill in the chart: DNA mRNA Triplet Codon tRNA Anticodon _______________ Amino Acid met GGA TTC UAG ORDER THE FOLLOWING _____ Intron sequences are spliced out and exons are joined together _____ amino acids form peptide bonds as tRNA molecules match the mRNA _____ RNA polymerase reads the DNA and builds complimentary sequence _____ The mRNA attaches to the ribosome _____ The ends of the mRNA are protected before it leaves the nucleus _____ RNA polymerase finds the promoter sequence on DNA _____ transfer RNA arrives at the ribosome and the anticodon complements to the mRNA codon Practice Questions: 1. Which process helps to preserve the genetic information stored in DNA during DNA replication? A. the replacement of nitrogen base thymine with uracil B. enzymes quickly linking nitrogen bases with hydrogen bonds 53 54 C. the synthesis of unique sugar and phosphate molecules for each nucleotide D. nucleotides lining up along the template strand according to base pairing rule 2. The endoplasmic reticulum is a network of membranes within the cell, and it is often classified as rough or smooth, depending on whether there are ribosomes on its surface. Which statement best describes the role of rough endoplasmic reticulum in the cell? A. It stores all proteins for later use. B. It provides an attachment site for larger organelles. C. It aids in the production of membrane and secretory proteins. D. It stores amino acids required for the production of all proteins. Use the diagram below to answer the question. 3. Which type of change in chromosome composition is illustrated in the diagram? A. deletion B. insertion C. inversion D. translocation 4. Which statement describes a cell process that is common to both eukaryotic and prokaryotic cells? A. Both cell types carry out transcription in the nucleus. B. Both cell types use ribosomes to carry out translation. C. Both cell types assemble amino acids to carry out transcription. D. Both cell types carry out translation in the endoplasmic reticulum. 5. A genetic mutation resulted in a change in the sequence of amino acids of a protein, but the function of the protein was not changed. Which statement best describes the genetic mutation? A. It was a silent mutation that caused a change in the DNA of the organism. B. It was a silent mutation that caused a change in the phenotype of the organism. C. It was a nonsense mutation that caused a change in the DNA of the organism. D. It was a nonsense mutation that caused a change in the phenotype of the organism. 6. Which of the following is primarily responsible for the coding of the amino acids used in the synthesis of cellular proteins? A. DNA 54 55 B. transfer RNA C. ribosomes D. Golgi apparatus 7. Which statement describes the diagram above? a. DNA transcription is producing ribosomal RNA. b. DNA translation is producing messenger RNA. c. DNA transcription is producing messenger RNA. d. DNA translation is producing ribosomal RNA. 8. Which organelle is not involved in the synthesis and secretion of a protein from the cell? a. ribosome. b. Smooth ER. c. Golgi apparatus. d. Plasma membran. 9. Which pair consists of terms that represent equivalent units of information? a. Codon : DNA b. Gene : polypeptide c. Chromosome : protein d. Nucleotide : amino acid 10. A tRNA molecule with which of the following anticodons would be able to bind to a molecule of lysine (has codons AAA or AAG)? a. TTT b. TTC c. AAA d. UUC 11. Suppose all of the ribosomes in a cell were destroyed. How would this most likely affect the process of gene expression? a. The DNA double strand would be unable to separate. b. The cell would be unable to form mRNA strands. c. The amino acids could not be joined to form a protein. d. The tRNA molecules would bind to the wrong amino acids. 55 56 Open-ended Question: 12. Consider the process of gene expression in a eukaryotic cell. Part A: Describe two similarities between transcription and translation: ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ __________________________________________________________________________________________ Part B: Describe two differences between transcription and translation ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ Part C: Identify one difference between the synthesis of proteins used within the cell and the synthesis of proteins that will be secreted from the cell. ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ 56 57 Theory of Evolution Keystone Eligible Content: • Explain how natural selection can impact allele frequency of a population • Describe the factors that can contribute to the development of new species (e.g. isolating mechanisms, genetic drift, founder effect, migration) • Explain how genetic mutations may result in genotypic and phenotypic variations within a population • Interpret evidence supporting the theory of evolution (i.e. fossil, anatomical, physiological, embryological, biochemical, and universal genetic code) • Distinguish between the scientific terms: hypothesis, inference, law, theory, principle, fact, observation Explain how natural selection can impact allele frequency of a population. 1. Distinguish between stabilizing, disruptive, and directional selection. A B C 2. Identify the type of selection in graph A _______________________________ 3. Identify the type of selection in graph B _______________________________ 4. Identify the type of selection in graph C _______________________________ 57 58 5. In a species of snail, dark individuals are better hidden (from bird predators) in the shady forest, while lighter individuals are better hidden in well lit brushy edge areas. There are no areas of intermediate brightness; therefore, ___________ acts on shell color in these snails. a. directional selection b. disruptive selection c. stabilizing selection 6. Small Aristelliger lizards have difficulty defending territories, but large lizards are more likely to be preyed upon by owls. This situation results in ________ on adult body size. a. directional selection b. disruptive selection c. stabilizing selection 7. Long necks make it easier for giraffes to reach leaves high on trees, while also making them better fighters in "neck wrestling" contests. In both cases, __________ appears to have made giraffes the long-necked creatures they are today. a. directional selection b. disruptive selection c. stabilizing selection Describe the factors that can contribute to the development of new species (e.g. isolating mechanisms, genetic drift, founder effect, migration) 8. Types of Reproductive Isolation: Behavioral Isolation Geographic Isolation Temporal Isolation 58 59 9. Populations of the same species of seal live on islands too far apart to swim between them for mating. a. behavioral isolation b. temporal isolation c. geographic isolation 10. Species of birds have elaborate courtship dances, and females select the best dancers as mates. a. behavioral isolation b. temporal isolation c. geographic isolation 11. Varieties of oak tree produce pollen during different seasons, so they can’t pollinate one another. a. behavioral isolation b. temporal isolation c. geographic isolation 12. Herds of caribou misinterpret each other’s mating behavior, so they fight instead of mating a. behavioral isolation b. temporal isolation c. geographic isolation 13. What is genetic drift? Explain how genetic mutations may result in genotypic and phenotypic variation within a population. 59 60 Interpret evidence supporting the theory of evolution (i.e. fossil, anatomical, physiological, embryological, biochemical, & universal genetic code) 14. Define and give an example of each of the following terms: Vocabulary Description Example(s) Homologous Structure Analogous Structure Vestigial Structure 15. DNA sequences are often used to determine relationships between organisms. DNA sequences that code for a particular gene can vary, though organisms that are closely related will have very similar sequences. This table shows the amino acid sequences of 4 organisms. Human: C C A T A G C A C C T A Chimpanzee: C C A T A A C A C C T A Pig: C C A T G T A A A C G A Cricket: C C T A A A G G G A C G Based on these sequences, which two organisms are most closely related? An unknown organism is found in the forest and the gene is sequenced as follows: Unknown: C C A T G G A A T C G A What kind of an animal do you think this is? Distinguish between the scientific terms: hypothesis, inference, law, theory, principle, fact observation 16. Describe the relationship between a hypothesis, an inference and a theory. 60 61 Assessment Anchor – Theory of Evolution: Explain how natural selection can impact allele frequency of a population. Use the circle graphs below to answer question 1. 1. The graphs illustrate change in a lizard population over time. Which process most likely led to the change in the lizard population? a. natural selection acting on a harmful trait b. natural selection acting on a beneficial trait c. natural selection acting on a dominant trait d. natural selection acting on a recessive trait 2. The frequency of an allele in a fly population changes from 89% to 20% after three generations. Which other events most likely occurred during the same time period? a. an environmental change and a fly population increase b. an environmental change and a fly population decrease c. interbreeding of flies with an invasive species and fly population speciation d. interbreeding of flies with an established local species and fly population speciation Use the graph below to answer question 3. 3. Tail length in mice varies within a population. Scientists observed change in the distribution of tail lengths in a mouse population over time. At the genetic level, what has most likely happened to the allele for the shortest tail lengths? a. The allele changed from being dominant to being recessive. b. The allele changed from being autosomal to being sex-linked. c. The allele became less frequent than the alleles for longer tail lengths. d. The allele began to code for long tail lengths instead of the shortest ones. 61 62 Describe the factors that can contribute to the development of new species (e.g. isolating mechanisms, genetic drift, founder effect, migration). 4. In North America, the eastern spotted skunk mates in late winter, and the western spotted skunk mates in late summer. Even though their geographic ranges overlap, the species do not mate with each other. What most likely prevents these two species from interbreeding? a. habitat isolation c. geographic isolation b. gametic isolation d. reproductive isolation Explain how genetic mutations may result in genotypic and phenotypic variations within a population. 5. A mutation occurs in the genes that code for coat color in deer. Which change will most likely result from this mutation? a. a change in the selection pressures acting on coat color b. a change in the coat-color genes of deer predator species c. an increase in coat-color diversity in the population d. an increase in the number of genes for coat color in the population Interpret evidence supporting the theory of evolution (i.e. fossil, anatomical, physiological, embryological, biochemical, and universal genetic code) Use the illustrations below to answer question 6. 6. The skeletons of mammalian forelimbs represent variations of a structure that was present in their common ancestor. What has most likely caused the variation in forelimbs? a. changes in muscle structure c. trait formation due to behaviors b. changes in the genetic codes d. development of vestigial structures 62 63 Use the table below to answer question 7. . 7. The gene COII is in the genome of many organisms. A comparison of the number of base differences between the COII gene in a rat and that of two other animals is shown. A. Based on the data, describe a possible evolutionary relationship between rats, mice, and cows. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ B. Describe how different organisms having a common gene such as COII supports the theory of evolution. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ C. The COII gene of a monkey has 203 base differences from the same gene in a rat and 201 base differences from the same gene in a mouse. Compare the evolutionary relationships between the monkey, the rat, and the mouse. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 63 64 Distinguish between the scientific terms: hypothesis, inference, law, theory, principle, fact, and observation. Use the table below to answer question 8. Student’s Observations of a Pond Ecosystem Quantitative Qualitative 37 fish and three frogs Leaves lie on the bottom of the pond 2 types of aquatic grass Water insects move along the water’s surface 12 small rocks and 1 medium rock All 3 frogs are sitting on a pond bank sand 8. A group of students measured a ten-square-meter section of a pond ecosystem and recorded observations. Which statement is a testable hypothesis? a. The frogs living in the pond represent a population b. Water is an abiotic component in the pond ecosystem c. If the fish are given more food, then they will be happier d. If the frogs are startled, then they will jump into the water 64 65 Ecology Keystone Eligible Content: • Describe the levels of ecological organization (i.e. organisms, population, community, ecosystem, biome, and biosphere) • Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems • Describe how energy flows through an ecosystem (e.g. food chains, food webs, energy pyramids) • Describe biotic interactions in an ecosystem (e.g. competition, predation, symbiosis) • Describe how matter recycles through an ecosystem (i.e. water cycle, carbon cycle, oxygen cycle, and nitrogen cycle) • Describe how ecosystems change in response to natural and human disturbances (e.g. climate change, introduction of nonnative species, pollution, fires) • Describe the effects of limiting factors on population dynamics and potential species extinction Describe the levels of ecological organization. 1. Use the terms below to list the six levels of ecological organization in order of increasing complexity. Then define each term. Community Ecosystem Biosphere Population Species/Organism Biome A – _________________________ - B – _________________________ - C – _________________________ - D – _________________________ - E – _________________________ - F – _________________________ - 65 66 Describe characteristic biotic and abiotic components of an ecosystem. 2. Identify four biotic and four abiotic components of the aquatic and terrestrial ecosystems shown below. Biotic Factors Abiotic Factors Describe how energy flows through an ecosystem (e.g. food chains, food webs, and energy pyramids) Use the food chain below to answer the next two questions. 3. Identify the original source of energy in this food chain. 4. What percent of energy is transferred from the second trophic level (deer) to the third trophic level (lion)? 66 67 5. Energy in an ecosystem (flows in one direction / cycles). (circle one) 6. Nutrients in an ecosystem (flow in one direction / cycles). (circle one) Use the food web below to answer the next question. 7. If the size of the mouse population were to decrease, which of the following would most likely happen? a. b. c. d. The rabbit population will increase. The lion population will decrease. The owl population will increase. The snake population will decrease. Describe biotic interactions in an ecosystem (e.g. competition, predation, symbiosis) Use the food chain below to answer the next two questions. 8. If the size of the insect population were to decrease, what effect would that have on the size of the mouse population? Explain your answer. 9. If the size of the owl population were to decrease, what effect would that have on the size of the mouse population? Explain your answer. 67 68 10. Match each example with the correct type of community interaction. a. Competition b. Parasitism c. Mutualism d. Commensalism ______ A leech feeds on the blood of a human. ______ A clownfish lives among the sea anemone’s tentacles and protects the sea anemone by chasing away would-be attackers. A sea anemone, in turn, protects the clownfish from predators. ______ A cow and a sheep feed on the same grass. ______ A tree provides nutrients and a sunlit location for the orchid living on it. Describe how matter recycles through an ecosystem (i.e. water cycle, carbon cycle, oxygen cycle, and nitrogen cycle) 11. Complete the diagram of the water cycle using the words below: Evaporation Transpiration Precipitation Condensation 68 Condensation Runoff 69 12. Complete the diagram of the carbon cycle using the words below: Burning fossil fuels Plant Respiration Animal Respiration Photosynthesis Decomposition 13. Complete the diagram of the nitrogen cycle using the words below: Denitrification Nitrogen Fixation Nitrification Atmospheric Nitrogen Ammonification 69 70 Describe how ecosystems change in response to natural and human disturbances (e.g. climate change, introduction of nonnative species, pollution, fires). 14. What is ecological succession? 15. Distinguish between primary and secondary succession. 16. Identify five ways that humans reduce biodiversity in an ecosystem. 17. How does the introduction of nonnative species threaten biodiversity? Describe the effects of limiting factors on population dynamics and potential species extinction. 18. What is a limiting factor? 19. Distinguish between density-dependent and density-independent limiting factors and give two examples of each type of limiting factor. 70 71 Assessment Anchor – Ecology: Describe the levels of ecological organization (i.e. organisms, population, community, ecosystem, biome, and biosphere). Use the list below to answer question 1. Observations • two grey wolves • five moose • several species of conifer trees • large granite rock • shallow pond 1. A student wrote several observations in a field notebook. Which term best classifies all of the student’s observations? a. population c. ecosystem b. food chain d. community Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems. 2. A researcher observing an ecosystem describes the amount of sunlight, precipitation, and type of soil present. Which factors is the researcher most likely describing? a. biotic factors in a forest c. abiotic factors in a prairie b. biotic factors in a tundra d. abiotic factors in an ocean Describe how energy flows through an ecosystem (e.g. food chains, food webs, energy pyramids). Use the diagram below to answer question 3. 3. Which sequence correctly describes the flow of energy between organisms in the marine food web? a. from seals to penguins to krill c. from sea birds to seals to penguins b. from whales to krill to small fish d. from small fish to penguins to seals 71 72 4. Scientists observed that the populations of top-level consumers in a particular ecosystem were rapidly decreasing. Further studies revealed that there was also a decline in producer productivity. Which other changes did the scientists most likely observe in the ecosystem? a. increased producer diversity b. decreased population size at all levels c. decreased primary consumer populations only d. increased primary and secondary consumer diversity Describe biotic interactions in an ecosystem (e.g. competition, predation, symbiosis). 5. A species of snapping turtles has a tongue that resembles a worm. The tongue is used to attract small fish. Which best describes the interaction between the fish and the snapping turtle? a. predation b. symbiosis c. parasitism d. competition Describe how matter recycles through an ecosystem (i.e. water cycle, carbon cycle, oxygen cycle, and nitrogen cycle). 6. Which statement correctly describes how nitrogen in the soil returns to the atmosphere? a. Soil bacteria convert nitrates into nitrogen gas. b. Decomposers directly convert ammonium into nitrogen gas. c. Plants assimilate nitrites and convert them into nitrogen gas. d. Nitrogen-fixing bacteria in plant roots convert nitrates into nitrogen gas. Describe how ecosystems change in response to natural and human disturbances (e.g. climate change, introduction of nonnative species, pollution, fires). 7. Agricultural runoff can carry fertilizers into lakes and streams. This runoff can cause algae populations to greatly increase. Which effect does this change in the algae population sizes most likely have on affected lakes and streams? a. an increase in water level b. an increase in water clarity c. a reduction in dissolved oxygen needed by fish and shellfish d. a reduction in temperature variations near the water’s surface Describe the effects of limiting factors on population dynamics and potential species extinction. 8. A farmer observed that an increase in a field’s soil nitrogen content was followed by an increase in producer productivity. What does this observation most likely indicate about the relationship between nitrogen and the producers in the field? a. Nitrogen was a biotic factor. c. Nitrogen became a surplus resource. b. Nitrogen was a limiting factor. d. Nitrogen became a selection pressure. 72 73 Use the graph below to answer question 9. 9. Isle Royale is located in Lake Superior. Isle Royale is home to populations of wolves and moose. The interactions between the wolves and moose, as well as the individual population sizes, have been studied since 1958. The graph shows the population sizes over time for both wolves and moose. A. Describe one limiting factor for the moose population. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ B. Explain one likely reason why the wolf population rapidly increased between 1975 and 1980. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 73 74 C. Predict what will happen to the moose population’s size after 1994 by describing the shape of the curve. In your answer, be sure to explain the reasoning behind your prediction. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 74
