AP BIOLOGY UNIT 2 TEST QUESTIONS WITH VERIFIED ANSWERS

AP BIOLOGY UNIT 2 TEST QUESTIONS WITH VERIFIED ANSWERS Compare and contrast P2 and P1. Photosystem II begins , which absorbs wavelengths at a wavelength of 680 nm. Here, energy is absorbed and passed along until it reaches P680 chlorophyll. When this chlorophyll is excited, it sends its electrons to the primary electron acceptor. Electrons are taken from H2O and passed to P680 to replace the electrons given to the primary acceptor. This forces O2 to form. The electrons are passed to photosystem 1 through the ETC (The light reactions also generate ATP, using chemiosmosis to power the addition of a phosphate group to ADP, which is photophosphorylation.) and the photosystem 1 electrons become excited, P1 passes the energy to its own primary electron acceptor, which are sent through the ETC , which donates the electrons to NADP+ to produce NADPH. Compare endocytosis to exocytosis. - Exocytosis: Substances are exported out of the cell, this is achieved through the fusion of vesicles with the plasma membrane. - Endocytosis: The cell takes in biological membranes by forming new vesicles from the plasma membrane. -- Phagocytosis: solids --Pinocytosis: fluids Define cellular respiration. -Glycolysis: Krebs Cycle: Oxidative Phosphoralaytion. - C6H12O6 + 602 = 6CO2 + ATP - Glycolysis: Believed to be ancient, and it occurs in the cytosol. It oxidizes glucose (6 carbons) to 2 Pyruvates. It makes 2 ATP and 2 NADH and 2H2O. No oxygen is required. -- 2 phases: Energy investment: The cell uses ATP to phosphorylate compounds of glucose. Energy payoff: 2 ATP is produced by substrate-level phosphorylation (ADP + P) and NAD+ is reduced to 2NADH by electrons released. Also, two 3-C compounds are oxidized. - Citric Acid Cycle/Krebs: Occurs in the matrix of the mitochondria. The pyruvate is converted to acetyl CoA, a process which also produces NADH. The acetyl CoA goes through an 8-step cycle that converts Citrate to Oxaloacetate. The pyruvate is eventually reduced to H2O and CO2. The net gain is 2 ATP, 6 NADH, and 2 FADH2 (the electron carrier). The ATP is produced by substrate level phosphorylation. - OP: Requires oxygen. The NADH and FADH2 produced are used to create ATP. The ETC is a collection of molecules embedded in inner membrane of the mitochondria. It alternates between a reduced/oxidized state as it accepts and donates electrons. Electrons removed from glucose by NAD+ during glycolysis and the citric acid cycle are transferred from NADH to the first molecule of the electron transport chain. Another source of electrons for the transport chain is FADH2, the other reduced product of the citric acid cycle. FADH2 adds its electrons at a lower energy level than NADH does. Both NADH and FADH2 provide 2 electrons for oxygen reduction, and the ETC eases the fall of electrons from food to oxygen. When oxygen accepts a pair of electrons, it pics up a pair of hydrogen ions to produce water. As electrons move through the ETC, proton pumps move H+ across inner mitochondrial membrane. This creates a proton gradient Define diffusion and osmosis. - Diffusion: The movement of molecules across their concentration gradient without the use of energy. - Osmosis: The passive diffusion of water down its concentration gradient across selectively permeable membranes. Water moves from a region of high water concentration to a region of low water concentration. Define photosynthesis. - 6H2O + 6CO2 + light = C6H12O6 + H2O + 602. - Light-dependent - Calvin Cycle - The light reactions convert solar energy to chemical energy of ATP and NADPH. They occur in the thylakoid. Chlorophyll absorbs the light, and one of its electrons is elevated to a higher energy level, the excited electron drops back down to the ground state, giving off heat in the process. This energy is passed along to chlorophyll a, which passes its electron to the primary electron acceptor. Photosystem II begins , which absorbs wavelengths at a wavelength of 680 nm. Here, energy is absorbed and passed along until it reaches P680 chlorophyll. When this chlorophyll is excited, it sends its electrons to the primary electron acceptor. Electrons are taken from H2O and passed to P680 to replace the electrons given to the primary acceptor. This forces O2 to form. The electrons are passed to photosystem 1 through the ETC (The light reactions also generate ATP, using chemiosmosis to power the addition of a phosphate group to ADP, which is photophosphorylation.) and the photosystem 1