Question

Which statement regarding phototrophs is correct?

a. Green sulfur bacteria appear green because their bacteriochlorophylls absorb green light.

b. The proton motive force generated during photosynthesis in purple bacteria generates reducing power.

c. Electron flow in oxygenic photosynthesis generates both cellular energy and precursor metabolites

d. Electron carriers associated with FeS-type photosystems achieve higher reduction potentials than in Q-type photosystems.

e. None of the above.

Which statement regarding autotrophy is incorrect?

a. A single turn of the Calvin Cycle fixes one molecule of CO2.

b. In green sulfur bacteria, the enzymes of the reverse CAC are not homologues of the enzymes of the CAC in E. coli.

c. Without regenerating ribulose bisphosphate, the Calvin Cycle would stall.

d. Unlike the Calvin Cycle, the Reverse Citric Acid Cycle does not consume reducing power when fixing CO2.

e. None of the above.

Which statement regarding N2 fixation is correct?

a. All electrons involved in fixing N2 are derived from pyruvate.

b. Cells growing by fermentation cannot fix N2.

c. Only cells that fix CO2 can fix N2.

d. N2 fixation by nitrogenase consumes a total of 6 electrons.

e. None of the above.

Answer 1

1)Electron flow in oxygenic photosynthesis generates both cellular energy and precursor metabolites

2) Unlike the Calvin Cycle, the Reverse Citric Acid Cycle does not consume reducing power when fixing CO2

3) N2 fixation by nitrogenase consumes a total of 6 electrons.