AP BIOLOGY EXAM 2021 questions with complete solutions

Water characteristics polar, cohesion (hold together), adhesion (hold to another substance), surface tension, specific heat, heat of vaporization Surface Tension A measure of how difficult it is to stretch or break the surface of a liquid Specific Heat amount of heat absorbed or lost to change temperature by 1C Heat of Vaporization the quantity of heat required to convert 1 from liquid to gas Water polarity uneven sharing of electrons that produces a negative charge near the oxygen atom and positive charges near each hydrogen atom Water properties solvent, cohesive, thermal Organic Chemistry the study of carbon compounds Hydroxyl OH-, alcohol/ethanol Carbonyl C=O, aldehyde, keytone Carboxyl O=C-OH, carboxylic acid as in acetic acid Amino H-N-H, amine as in tryptophan Sulfhydryl R-SH four organic compounds carbohydrates, lipids, proteins, nucleic acids Monosaccharides glucose, fructose, galactose Disaccharides sucrose, lactose, maltose Polysaccharides glycogen, starch, cellulose Glycogen storage polysaccharide form of glucose in animals Starch storage polysaccharide form of glucose in plants Cellulose Carbohydrate component of plant cell walls. Condensation v. Hydrolysis Condensation: anabolic, water out Hydrolysis: catabolic, water in Protein (condensation/hydrolysis) Amino acid ---> dipeptide ---> polypeptide Carbohydrates (condensation/hydrolysis) Monosaccharide ---> Disaccharide ---> Polysaccharide Glycosidic bond bond formed by a dehydration reaction between two monosaccharides (+ water in product) 2 families of nitrogenous bases pyrimidines and purines Complementary base pairing A & T = 2 hydrogen bonds C & G = 3 hydrogen bonds DNA Structure Phosphodiester: between phosphates & sugars Covalent: between sugar & base pair Hydrogen: between base pairs Protein Structure amino group-r side chain-carboxyl group Primary amino acid sequence, peptide bonds Secondary representing local structure, held by H+ bonds Tertiary folding of a single protein Quaternary protein complex Two forms of proteins globular (insoluble, structural) and fibrous (soluble, functional) Fibrous proteins long, insoluble, structural proteins (keratin, elastin) Globular proteins chunk, soluble (amylase, insulin, hemoglobin, immunoglobin, transport pumps) Anabolic reactions build complex molecules from simpler ones, endergonic, biosynthetic (example: photosynthesis) Catabolic reactions breakdown of molecules, exergonic, degradative (example: cellular respiration) First Law of Thermodynamics Energy can be transferred and transformed, but it cannot be created or destroyed. Second Law of Thermodynamics Every energy transfer makes the universe more disordered = increases entropy Free energy amount of energy available to do work...ΔG =ΔH−TΔS ΔG (Gibbs) change in free energy ΔH (enthalpy) change in total energy ΔS change in entropy T temperature in K