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By: Zack White Table of Contents Chapter 10 Chapter 11 Chapter 14 Chapter 16 Chapter 15.3 and 17.1 Chapter 17.4 Chapter 19 Nervous System Notes Chapter 10 Limits to Cell Growth DNA Overload! Inefficient exchange of materials! Cell volume increases too rapidly! The solution: Cell Division Cells that do not divide throughout life would not encounter the issues above. DNA determines cell decline and death! What are Chromosomes? Strands of DNA Every organism has a specific number of chromosomes. Before cell division occurs, DNA must be copied so each new cell will have DNA. Once copied, the two identical stands (or Chromatids) are held together by a Centromere Cell Cycle Interphase – growth period of cell, longest stage of cell life. 1. G1 phase – growth 2. S phase – DNA replication 3. G2 phase – preparation for mitosis Cell Division – division of the cell into 2 1. Mitosis – division of the cytoplasm 2. Cytokinesis – division of the cytoplasm Mitosis Prophase – chromatin condenses, centrioles separate to opposite sides of cell (animal cells only), spindle forms, nuclear membrane breaks down Metaphase – Chromosomes line up in the middle Anaphase – Sister chromatids separate Telophase – chromosomes gather at opposite ends, new nuclear membranes form Cytokinesis Division of the cytoplasm In animal cells: cleavage of cell membrane. In plat cells: a cell plate forms midway between the divided nuclei. Table of Contents Cancer Uncontrolled cell division DNA or proteins damaged by carcinogens or genetically inherited. Carcinogens: radiation, chemicals, viral End of Chapter 10 Notes!!!!!!!!!!!!!!!!!!!!!!!!! Chapter 11 Notes Chromosome Number Each organism inherits 1 set of chromosomes from “mom” and 1 set from “dad”. (ex. In humans…) A homologous pair = 1 chromosome pair A diploid cell = 2 whole sets A haploid cell = 1 set (ex: sex cells) Meiosis Reduction division What is it!? Two stages: Meiosis I and Meiosis II Meiosis I: Important events that take place: a. Pairing of tetrads What is tetrad? b. Crossing over What happens? c. Reduction division Meiosis II: same process as mitosis (no real interphase II thus no 2nd S-phase) Table of Contents Gamete Formation Males Produce 4 sperm from 1 cell Each are haploid Female Produce haploid eggs Cell divisions are uneven Only one cell receives most of the cytoplasm Other smaller cells are called polar bodies End of Chapter 11 Notes Chapter 14 Notes Human Chromosomes Karyotype: picture of chromosomes that are arranged in 23 pairs. Autosomes are pairs #1-22. Sex chromosomes are pair #23 -Males have one X and one Y (XY) -Females have two X’s (XX) Human chromosome number is written as: 46XX for a female and 46XY for a male Autosomal Genetic Disorders Recessive alleles – two recessive alleles to show disorder Ex: PKU, cystic fibrosis, albinism Dominant alleles – only one dominant allele needed to show disorder. Ex. Huntington’s disease, achondroplasia Codominant alleles – only one codominant allele needed to show disorder. Ex. Sickle cell anemia Sex-Linked Traits Location: Sex chromosomes, pair #23 Most sex chromosome disorders are found on the “X” chromosome of pair #23 Males only need 1 allele for the trait. Females need 2 alleles for the trait. Colorblindness – lack of ability to distinguish certain colors Hemophilia – lack of a clotting factor in blood. Duchenne Muscular Dystrophy – defective muscle protein that causes progressive weakening and loss of skeletal muscle. Table of Contents Chromosomal Mutations 1. 2. 3. 4. 5. Meiosis goes wrong at Anaphase I. Homologous pairs don’t separate Called: Nondisjunction Down Syndrome – 57XX or 47XY Klinefelter’s Syndrome – 47XXY Turner’s Syndrome – 45XO Metafemale – 47XXX or 48XXXX Jacob Syndrome – 47XYY ~!End of Chapter 14 Notes!~ Chapter 16 Notes Gene Frequencies and HardyWeinberg Gene frequencies can be high or low no matter if the allele is dominant or recessive. Frequencies can change depending on the conditions that exist in the environment. It is the changes in gene frequencies over time that results in evolution. Hardy-Weinberg In 1908 Hardy-Weinberg made a principle that provides a way to determine whether gene frequencies have changed in a population, and thus, whether evolution has occurred. Hardy-Weinberg Principle This principle will be maintained in nature only if all five of the following conditions are met: 1. Very large population 2. Isolation from other populations 3. No net mutations 4. Random mating 5. No natural selection Hardy’s Equations P+q=1 P = frequency of dominant allele Q = frequency of recessive allele P2 + 2pq + q2 = 1 P2 = frequency or % homozygous dominant genotype 2pq = frequency or % heterozygous genotype Q2 = frequency or % homozygous recessive genotype Evolution Definition: Change over time Occurs on populations, not individuals. (Individuals do note evolve, but are part of populations which do.) Evolution is the genetic change occurring in a population of organisms over time. Darwin’s Natural Selection is the mechanism that runs evolutionary theory… Evolution by Natural Selection The Struggle for Existence (compete for food, mates, space, water, etc.) Survival of the Fittest (strongest able to survive and reproduce) Works upon the PHENOTYPES not the genotypes of any population. Darwin’s Observations In any population, there is variation with no two individuals being exactly alike. Much of this variation between individuals is inheritable What are the Sources of Variations? Gene shuffling and crossing over from Meiosis. Zygote production or fertilization Mutations What is a Gene Pool? All the alleles or genes for all the traits for a given population. How common is a particular allele in a gene pool is its: GENE FREQUENCY What is an adaptation? Any trait that increases an animal’s chance for survival in a particular environment. Those with the best adaptation for the environment are the FITTEST and will reproduce more. Patterns for Natural Selection Single-Gene trait – only two alleles, with two distinct phenotypes; show all-o-nothing pattern from natural selection. Polygenic Traits – many allele possibilities with several phenotypes; show continuous variation just shifts in distribution Ex: directional, stabilizing, Artificial Selection Humans slelect those traits they found most useful Domesticated animals Dog breeds Milk production in cows Genetically engineered crops What if natural selection does not play a role in gene frequency? GENETIC DRIFT Notes 16.3 In the process of evolution, natural Selection and genetic drift can lead to the ultimate differentiation…Speciation What is a species? A group of similar organisms that can breed and produce fertile offspring. So, once members of two populations cannot interbreed and produce fertile offspring, they are considered 2 different species They are reproductively isolated How could this happen!?!?!?!? Some Isolating Mechanisms Geographical – barriers such as rivers, mountains or bodies of water separate a population Behavioral – different courtship rituals Temporal – reproduce at different times of the year Darwin’s Finches is an example of speciation Finches on the islands resembled a mainland finch More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects) Finches had different types of beaks adapted to their type of food gathering Table of Contents Speciation of Darwin’s Finches Founders Arrive – few finches from the island from the South American mainland reach island. Separation of Populations – Geographic isolation by being on different islands Changes in gene pools – by natural selection Reproductive isolation – do not recognize behaviors or physical traits etc. Continued evolution over many generations End of Chapter 16 Notes!!!! What Evidence is there for Evolution? Sections 15.3 and 17.1 Fossil Record The Fossil Record – incomplete record of life on earth -sedimentary rock forms most fossils -proves life on earth has changed over time Relative Dating – estimating a fossil’s age by comparing it with other fossils Radioactive Dating – calculation of sample’s age based on the amount of radioactive isotope it contains. Geographic distribution of species Unrelated species share similarities because of similar adaptations to the environment. Biochemical Similarities All organisms use DNA or RNA; cell respiration process Homologous Structures Same embryonic origin but have different mature forms. Vestigial organs are useless structures that many have been used by ancestors. Embryology Embryonic cell development patterns are the same in all vertebrates Descent with modification Species today look different from their ancestors because they have similar traits Each living species has: -descended -with changes -from other species -over time Table of Contents Common Descent All living things were derived from common ancestors Cladograms can help to show this End of 15.3 and 17.1 Notes Evolution patterns 17.4 Macroevolution Large-scale evolutionary patterns and processes that occur over long periods of time Microevolution Small-scale changes in allele frequencies over a few generations at or below the species level A Driving Force of Evolution: Extinction More than 99% of all species that had ever lived on earth are now extinct. Usual reasons: competition, environmental changes Mass extinctions account for large changes wiping out entire ecosystems Leaving many open niches to be filled by those that survived. Divergent Evolution Many species developing from one. A.k.a. Adaptive Radiation Example: Darwin’s finches Evolving through natural selection Usually a slow process Disappearance of dinosaurs cleared the way for adaptive radiation of mammals. Convergent Evolution Process where unrelated organisms come to resemble each other or have similar looking traits. Environmental conditions are the same. Convergent evolution may lead to the formation analogous structures Table of Contents Coevolution Two species evolve in response to changes in each other over time. Formation of symbiotic relationships Advantages: less competition Disadvantages: too specific End of 17.4 Notes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Chapter 19 Viruses and Bacteria What is a virus? Ultramicroscopic infectious agents that replicates itself only within cells of living hosts. Many are pathogenic Composed of a piece of nucleic acid wrapped in a thin coat of protein. Virus Genetic Material DNA fairly stable from radical mutations Ex: polio, small pox RNA Mutations are common Retroviruses Ex: influenza, HIV Viral Reproduction Types Lytic Cycle Quick in process Takes over host cell Forces host to make more virus Uses host’s materials Destroys host cell Lysogenic Slower process Prophage inserted into host’s DNA Hides in host’s DNA until activated Once activated, continues with lytic cycle How fast can they replicate A virulent virus may complete its lifecycle in 30 minutes, producing 200 new viruses. Flu of 1918 killed people over 24 hours. How can a viral infection be cured There is no cure for a viral infection Vaccines must be taken before you are infected Once infected, body must fight off the infection Antiviral drugs are available to treat only a few viral diseases Prion Protein infectious particles No genetic material Diseases: Mad Cow, scrapie and Creutzfeldt-Jacob Nervous tissue with prions must be ingested Diseases See Textbook Figure 19-5 What is a Prokaryote An organism with no nucleus and unicellular. ALL BACTERIA!!!!!!!!!!!!!!!!!!!!!!!!! Classification Movement Non-Motile Flagella Slime Bacteria Shapes Three basic – Bacillus (rod), coccus (sphere), and spirillum (spiral) Gram Staining Technique Cell Walls: thick or thin peptidoglycan walls. Gram staining is used to identify. Metabolic Diversity Heterotrophs Chemoheterotroph Photoheterotroph Autotrophs Photoautotrophs Chemoautotrophs Energy Release Two ways: respiration and fermentation Classified based on how they release energy from food: Obligate aerobes Obligate anaerobes Facultative anaerobes Growth and Reproduction Binary Fission – simple mitosis Conjugation – Swapping genetic material Endospore Formation – thick coat for dormant times. Bacterial Importance Photosynthesis Decomposers – sewage treatment Nitrogen Fixers – fertilizer for plants Biological – vitamin K production, fiber breakdown Genetic Engineering – production of hormones for medical purposes Disease Pathogen – disease causing agent Cell and tissue destruction of infected organism. Food consumption of bacteria Releases toxins that poison the host and cause symptoms of disease. Prevention and Control Vaccines – given to prevent illness Antibiotics – given after infection to kill bacteria -Over usage problems -Conjugation Sterilization – exposure to high heat Disinfectants – chemical solutions Refrigeration Cooking Canning and Preservatives Chapter 40 Notes The Immune System Immune System Function To recognize, attack, destroy, and remember pathogens that invade our body. Two types of defense systems Nonspecific defense Specific defense Nonspecific Defenses Does not discriminate between any type of threat – Attacks all Provided by physical or chemical barriers 1st Line of Defense Skin and Mucus membranes (skin pH and stomach, saliva, tears, sticky mucus traps) 2nd line of defense: inflammatory response and fever Blood vessels dilate from histamine release, phagocytes move in Body temperature increase slows down pathogen growth and speeds up WBC response. Interferon – chemical secreted by infected cells to protect other cells from infection. Specific Immune Defense Two pathways that will occur 1. Humoral – antiobodies are made 2. Cell Mediated – destruction of infected cell or pathogen Key players: Lymphocytes Both pathways are activated when a pathogen invades the body. Humoral Antibodies are made to attach to a specific pathogen’s antigens. Immobilizing pathogen. Antigens are identifying surface markers. Key players: B cells Key steps: 1. B cells recognize antigen 2. B cell differentiates into plasma cells 3. Plasma cells make/release antibodies. 4. B cell differentiates into memory B’s Antibodies Y structured molecule made of protein. Specific receptor sites made to bind to specific antigens. Binds to the pathogen, flagging it for death Cell-mediated Immune Response Key players and steps: 1. Killer (cytotoxic) T-cells will multiply and attack cells with antigen markers. 2. Helper T’s will activate killer T’s and differentiate into memory T’s for future exposures. 3. Suppressor T’s will slow or stop the killer T’s when the attack is under control. 4. Macrophages clean up the mess The Germ Theory What is a disease Any change that disrupts normal functions of the body. What are some agents that produce disease? Bacteria, viruses, fungi, helminths, protists How can agents be transmitted? Physical contact, contaminated food, water, and infected animals (vectors) What methods do we use to fight infections disease? Antibiotics, vaccines, sanitation, pesticides Germ theory of Disease Idea that microorganisms can cause disease Based on observations from Louis Pasteur and Robert Koch. Robert Koch developed a set of rules “Postulates” for testing whether or not an organism caused disease. Koch’s Postulates 1. The pathogen should always be found in the body of a sick organism and not in a healthy one. 2. The pathogen must be isolated and grown in the lab in a pure culture. 3. When purified pathogens are placed in a new host, they should cause the same disease that infected the host. 4. The very same pathogen should be reisolated from the second host. And it should be the same as the original pathogen. Immunity Types Active Immunity – injection of a weak or mild form of pathogen; may make you a little sick. Attenuated form of disease. Natural exposure to pathogen. Long-term immunity. Passive Immunity – injection of antibodies from another organism; temporary immunity or treatment. Allergies An overreaction of the immune system Mast cells release histamines when allergic antigens attach to it. Result: itchiness, mucus production, sneezing, watery eyes etc. Asthma Narrowing of the air passages by the spasm contractions of the smooth muscle. Chronic disease Reaction to antigens or stress related. Other diseases Autoimmune Disorders Your own immune system is attacking yourself Production of “antiself” antibodies. Ex. Multiple Sclerosis, Rheumatoid arthritis, Lupus Immunodeficient Diseases Failure of the immune system to develop normally. Pathogen could be destroying WBC’s Ex: AIDS, boy in the bubble Chapter 18 Classificiation Why classify To organize living things into groups with biological meaning Taxonomy: the study of classification Assigning a name Problem: common names can vary among languages Solution: Latin and Greek words are commonly used to avoid any language issues Problem: When naming by specific traits too many words are used Solution: Carolus Linneaus developed 2-part naming system used today called Bionomial Namenclature Rules: 1. Always italicized 2. 1st word cap, 2nd lowercase 3. Genus is 1st word, species 2nd Kingdoms and Domains Modern tree contains six kingdoms and their phyla: Eubacteria, archaebacteria, protista, fungi, plantae, animalia Domains – newest larges inclusive category devloped from comparing rRNA subunits. Bacteria, Archaea, Eurkarya Modern Classification Just using appearance can be misleading New system uses: 1. Fossil 2. 2. Dissections/Comparative anatomy 3. 3. Molecular similarities/DNA/enzymes 4. 4. Evolutionary similarities or developmental milestones Molecular Clocks Comparing DNA segments and looking for mutations in similar genes. The more dissimilar the genes the longer ago they shared a common ancestor. Nervous System Notes CNS Consists of the brain and spinal cord Recieves sensory input, integrates and relays information for a response. Peripheral Nervous System All nerves from spinal cord and cranial region. 1. Sensory nerves pick up stimuli 2. Motor nerves send response to muscle organs Motor functions are controlled by a. Somatic nervous system, conscious control, skeletal system b. Autonomic nervous system, involuntary actions, heart, glands etc. Meninges Membranous coverings of the CNS CSF (cerebrospinal fluid) flows here Cerebrum Two hemispheres Connected by the Corpus Callosum Wrinkles or folds (gyri) increase neuron space. Four lobes: frontal, parietd, temporal, occipital Cerebral cortex – gray matter, outermost Cerebellum Beneath the occipital lobes of cerebrum Function – coordination of voluntary movements, maintains posture, integrates balance, information (equillbrium) Brain Stem 1. 2. 3. Connects the cerebrum to spinal cord Primary life functions Three sections Midbrain Pons Medulla Oblongata Other structures Thalamus – main relay station for sensory impulses; general awareness Hypothalamus – regulates HR, BP, temperature, hunger, sleep, waterfullness, stimulate pituitary Pituitary gland – major endocrine glands secretes hormones to control other glands/organs.