AP BIO Quarter One Study Guide

Evolution Evolution: change in allele frequency (genetics) of a population Change over time Populations evolve, individuals do not No genetic change no evolution EXAMPLE: Natural Selection: the process whereby organisms better adapted to their environment tend to survive and produce more offspring. Artificial Selection: when humans decide what mates with what Sexual Selection: when the traits selected increase chances of mating Gene Flow: immigration/emigration Genetic Drift: bottle neck effect and founder effect (decreases genetic variability) Hardy-Weinberg: no evolution is taking place No Mutations Prevents: mutations No Immigration/Emigration Prevents: Gene Flow Random Mating Prevents: Sexual Selection/Artificial Selection No Natural Selection Prevents: Natural Selection Large Population Prevents: Genetic Drift Population Genetics – study of how populations change genetically over time Population – Group of same species individuals that can and do interbreed successfully Gene pool – all of the alleles at all loci in all the members of a population Fixed – only one allele exists for a locus in the population Gene: Region of DNA Allele: form of a gene, series of nucleotides A: dominant allele a: recessive allele Genotype: combination of alleles Phenotype: physical trait manifestation of alleles Homozygous dominant: AA Heterozygous: Aa Homozygous recessive: aa p+q= 1 f(A)= p f(a)=q p2+2pq+q2=1 f(AA)=p2 f(Aa)=2pq f(aa)=q2 p2+2pq=dominant phenotype q2=recessive phenotype Lamark Theory of Inherited Characteristics: theory that If an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring. EXAMPLE: Parents are body builders. They have baby. Baby is born swol. VERY WRONG Mutation: a change in the nucleotide sequence of an organism’s DNA or in the DNA or RNA of a virus Substitution Silent: no change in amino acid Missense: changes 1 amino acid Nonsense: changes 1 amino acid into a stop codon Frameshift: (insert or deletion) EXAMPLE: CATCAT CATGCAT Speciation For speciation to occur: A barrier must form Reproductive isolation must take place Allopatric: somewhere new speciation occurs due to geographic barrier Sympatric: speciation not due to a geographic barrier Microevolution: evolution of a population or species Macroevolution: Evolution of more than one species Barriers Prezygotic Postzygotic Premating Post mating Geographic: Habitat Temporal (Separated by time) Behavioral Different communication EX: birds of paradise sex dance Mechanical Physically separating due to different reproductive organs Gametic Different chromosome numbers Reduced Hybrid Vitality Hybrid does not survive until adulthood Reduced Hybrid Fertility Sterile Hybrid Breakdown First generation reproduces, but second fails or dies Allopolyploidy Autopolyploidy Meteorites or Miller-Urey experiment: meant to prove life was possible in earth’s early environment Occham’s Razor: simplest explanation is best(meteorite) All cells have: Cell membrane Ribosomes Cytoplasm DNA Prokaryote: first living thing Unicellular Asexual Anaerobic Heterotrophic Order of change: Heterotrophic Autotrophic Anaerobic Aerobic Asexual (binary fission) Sexual Reproduction Unicellular Multicellular LUCA = Last Universal Common Ancestor (would be prokaryotic) Three eras: Paleozoic Mesozoic Cenozoic Mass Extinction: The extinction of species within a relatively short period of geological time, thought to be due to factors such as a catastrophic global event or widespread environmental change that occurs too rapidly for most species to adapt. Ordovician Devonian Permian Triassic Cretaceous Dehydration Synthesis (condensation): Removal of water from molecules to build a complex molecule from simpler components Hydrolysis: Uses water to break up the covalent linkages Splits apart polymers Reverse of dehydration synthesis Functional Groups: Macromolecules Carbohydrates Monomer = monosaccharides Example: Glucose Polymer = polysaccharides = Carbohydrate Example: Energy- Glycogen, Starch Structure: Cellulose, Chitin Bond = Glycosidic linkages = polar covelant 40735258890000Nucleic Acid Monomer = nucleotide Polymer = polynucleotide = Nucleic Acid DNA is held together with hydrogen bonds Made up of: Pentose Sugar: Deoxyribose (DNA) OR Ribose (RNA) 367919010668000Nitrogenous Base Purines: two rings Adenine, Guanine Pyrimidines: one ring Cytosine, Thymine, Uracil Adenine and Thymine are double bonded Cytosine and Guanine are triple bonded Phosphate group DNA RNA Strands Double Single Sugar Deoxyribose Ribose Nitrogenous Bases C, G, A, T C, G, A, U Progression DNA RNA RNA Protein The number of ribose carbons is the basis for identification of 5’ and 3’ ends of DNA and RNA strands 5’ 3’ 5’ end: phosphate only attached to 1 sugar 3’ end: sugar only attached to 1 phosphate Double stranded 5’ end and 3’ end in opposite direction Lipids: non-polar and not a polymer Fats: long-term energy storage and insulation Made up of: glycerol and 3 fatty acids To bond the three fatty acids, produce 3 H20 Bonded with ester linkages Saturated, Unsaturated, and Trans Fats Sterols: Regulate growth and development Phospholipids: form the membranes that enclose cells 37592008445500Saturated No double bonds in the fatty acid Animal fats Linked to heart disease Solid at room temperature Saturated fat structure is a straight line Saturated bonds: all bonds between carbon atoms are single in a saturated fatty acid (carbon chain is straight). The straight chain allows molecules to pack tightly among other similar molecules. 418211013335000Unsaturated At least one bond Plant fats Called oils Liquid at room temperature Double bonded causing it to be bent Unsaturated bonds: double bonds between two carbons make an unsaturated fatty acid (carbon chain has kinks). Kinks prevent close packing. Trans Fats Do NOT occur naturally (only in labs) Unsaturated fats a chemically “saturated” with hydrogen atoms. Also called Partially saturated hydrogenated vegetable oils. Phospholipids Similar to fats but only has 2 fatty acids Also has a phosphate group Hydrophilic head Choline (positive charge) Phosphate (negative charge) Hydrophobic tails Glycerol 2 Hydrocarbon chains (fatty acids) 368744517145000 Steroids Considered lipids because they are hydrophobic Consists of 4 fused hydrocarbons Example: Cholesterol 275399520574000Proteins Monomer = amino acid Polymer = polypeptide = protein Peptide bond = Polar covalent bond Made up of: Amine group: NH2 (basic) Carboxyl group: COOH (acidic) Primary Structure Sequence of amino acids Polar covalent bonds link the amino acids Only level that doesn’t use hydrogen bonds Secondary Structure Hydrogen bonding between amino acid side groups The sequence of amino acids, converts into 1 of 2 forms: -helix -pleated sheets 275336045720000 4036695000Tertiary Structure 3D shape of polypeptide Many types of bonds/interactions between side groups Bonds (Strongest to weakest): Disulfide bridge, hydrogen bond, ionic, hydrophobic interaction Disulfide bridges are most important here Quaternary Structure 2 or more polypeptide Same bonds and interactions as tertiary structure Chaperonins Proteins that assist the proper folding of other proteins Provide stable, insulated environment for a polypeptide to achieve the correct conformation Cell Organelles Nucleus Includes: Nuclear envelop: double membrane enclosing the nucleus; perforated by pores; continuous with ER Nucleolus: non-membranous structure involved in production of ribosomes; a nucleus has one or more nucleoli Chromatin: material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes Endoplasmic Reticulum: Network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-studded) and smooth regions Rough ER Secretes proteins made by ribosomes attached to the rough ER ER membrane keeps secretory proteins separate form proteins that remain in the cytosol, which are produced by free ribosomes. Rough ER is a membrane factory for the cell; it grows in place by adding membrane proteins and phospholipids to its own membrane As a polypeptide chain grows from a bound ribosome, the chain in threaded into the ER lumen through a pore formed by a protein complex in the ER membrane. The new polypeptide folds into its functional shape as it enters the ER lumen. Secretory proteins depart from the ER wrapped in the membranes of vesicles that bud like bubbles from a specialized region called transitional ER Smooth ER Synthesis of lipids, metabolism of carbohydrates, Ca^2+ storage, detoxification or drugs and poisons Ribosome: complexes that make proteins; free in cytosol or bound to rough ER or nuclear envelop complexes made of ribosomal RNA and protein, are the cellular components that carry out protein synthesis not an organelle high rates of protein synthesis = large number of ribosomes build proteins in two cytoplasmic locales: free ribosome: suspended in the cytosol bound ribosomes: attached to the outside of the endoplasmic reticulum or nuclear envelop Plasma Membrane: membrane enclosing the cell made of a phospholipid bilayer Mitochondrion: organelle where cellular respiration occurs and most ATP is generated two membrane enclosing the mitochondrion is a phospholipid bilayer with embedded proteins The outer membrane is smooth, but the inner membrane is convoluted, with infoldings called cristae. As highly folded surfaces, the cristae give the inner mitochondrial membrane a large surface area, thus enhancing the productivity of cellular respiration. The inner membrane divides the mitochondrion into two internal compartments. The first is the intermembrane space, the narrow region between the inner and outer membranes. The second is the mitochondrial matrix, is enclosed by the inner membrane. The matrix contains many different enzymes as well as mitochondria DNA and ribosomes. Enzymes in the matrix catalyze some of the steps of cellular respiration. Chloroplast: photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules The contents of a chloroplast are partitioned from the cytosol by an envelope consisting of two membranes separated by a very narrow intermembrane space. Inside the chloroplast, is another membranous system in the form of flattened, interconnected sacs called thylakoids. Thylakoids are stacked like poker chips; each stack in called a granum. The fluid outside the thylakoids is the stroma, which contains the chloroplast DNA and ribosomes as well as many enzymes. Golgi Apparatus: organelle active in synthesis, modification, sorting and secretion of cell products modification of proteins, carbohydrates on proteins, and phospholipids; synthesis of many polysaccharides; sorting of Golgi products, which are then released in vesicles Vesicles move from the ER to Golgi. Vesicles coalesce to form new cis Golgi cisternae. Cisternal maturation: Golgi cisternae move in a cis-to-trans direction. Vesicles from and leave Golgi, carrying specific products to other locations or to the plasma membrane for secretion. Vesicles transport some proteins backward to less mature Golgi cisternae, where they function. Vesicles also transport certain proteins back to ER site of function. Flagellum: motility structure present in some animal cells, composed of a cluster of microtubules within an extension of the plasma membrane Centrosome: region where cell’s microtubules are initiated; contains a pair of centrioles Cytoskeleton: reinforces cell’s shape; functions in cell movement; components are made of proteins. Includes: microfilaments, intermediate filaments, and microtubules Microvilli: projections that increase the cell’s surface area Peroxisome: organelle with various specialized metabolic functions; produces hydrogen peroxide as a by-product and then converts it to water Lysosome: digestive organelle where macromolecules are hydrolyzed Central Vacuole: prominent in older plant cells; functions include storage breakdown of waste products, and hydrolysis of macromolecules; enlargement of vacuole is a major mechanism of plant growth Plasmodesmata: cytoplasmic channels through cell walls that connect the cytoplasm of adjacent cells Cell wall: outer layer that maintains cell’s shape and protects all from mechanical damage; made of cellulose, other polysaccharides, and proteins