BIOC 385 Final Exam Questions with Correct Answers Latest Update

BIOC 385 Final Exam Questions with Correct Answers Latest Update Protons are pumped by mitochondria during active electron transport - Answers outside the inner mitochondrial membrane. Which is NOT involved in the transfer of reducing equivalents from succinate to molecular oxygen (O2)? - Answers complex I What is the reaction catalyzed by complex III in the electron transport system? - Answers UQH2 + cytochrome c+ --- UQ + cytochrome c A characteristic of complex III is that it - Answers uses the Q cycle mechanism to oxidize ubiquinone. Complex IV in the mitochondrial electron transport chain belongs to which enzyme class? - Answers oxidoreductase What is the location of the electron transport system protein called cytochrome c? - Answers intermembrane space What enzyme uses the proton motive force for its driving force? - Answers ATP synthase What best describes the driving force for ATP synthesis in the mitochondria? - Answers The higher pH inside the mitochondria that results from electron transfer. The catalytic headpiece of the ATP synthase enzyme is primarily composed of which subunits? - Answers a hexameric alpha3beta3 ring The ATP synthase enzyme contains a central stalk embedded in the mitochondrial membrane. What part of this stalk rotates? - Answers the ring of c subunits ATP synthesis occurs - Answers at the ATP synthase complex after ADP and Pi are transported into the mitochondria. What is the driving force for ATP synthesis by the ATP synthase enzyme? - Answers The pH gradient across the inner mitochondrial membrane. An ATP synthase enzyme with more than 10 c subunits in the F0 stalk would - Answers require more protons to complete one 360 degree rotation. What would happen to a mutated ATP synthase enzyme where the proton binding aspartate residue on the c subunits was mutated to an alanine? - Answers The enzyme would not make ATP in the presence of a proton gradient. Which part of the native ATP synthase enzyme is stationary and does NOT rotate during ATP synthesis? - Answers the catalytic headpiece How many ATPs are produced from the complete metabolism of one glucose molecule, assuming that all resulting NADH and FADH2 is used by the electron transport chain and oxidative phosphorylation to make ATP? - Answers 32 The main activator molecule of the ATP synthesis and the electron transport system is - Answers ADP. What would happen if mitochondria were treated with a proton gradient uncoupler, such as 2,4-dinitrophenol? - Answers Protons would be pumped by the mitochondrial electron transport chain, although no ATP would be synthesized. Chlorophyll absorbs - Answers photon energy and becomes excited or oxidized On excitation by a photon, a fate of the excited chlorophyll molecule is to - Answers transfer an electron to an acceptor molecule. For photosynthesis, sunlight energy drives electron transfer. Where are the electrons ejected from when light is absorbed? - Answers light-harvesting pigments in PSI and PSII Chlorophyll absorbs light energy efficiently because of the - Answers alternating double and single bonds. Which of the following is a photosynthetic light harvesting pigment? - Answers β-carotene Which of the following is an electron transfer molecule in photosynthesis light reactions? - Answers plastoquinone What group in photosystem II (PSII) directly reacts with H2O during its light-driven oxidation? - Answers oxygen evolving center To form one O2, __________ electrons must leave two water molecules, and to form one NADPH, __________ electrons must be delivered to one NADP+. - Answers 4; 2 In the chloroplasts, photosystem I (PSI) and photosystem II (PSII) are known to localize in different regions. PSI generally localizes in the __________, whereas PSII localizes in the __________. - Answers thylakoid lamellae; thylakoid grana In what location of the cell does the Calvin cycle occur? - Answers chloroplast stroma The Calvin cycle requires which species from the light reactions? - Answers ATP and NADPH The first stage of the three-stage Calvin cycle - Answers is catalyzed by the enzyme rubisco. In C3 plants CO2 is first incorporated into __________, whereas in C4 and CAM plants the CO2 is first incorporated into __________. - Answers 3-phosphoglycerate; oxaloacetate C4 plants are thought to be more efficient than C3 plants because they - Answers can