CLEP Biology Cellular Respiration and Photosynthesis 2

Question 1

Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA during pyruvate oxidation?

Accepted Answer

Pyruvate dehydrogenase complex

Answer

Pyruvate kinase

Answer

Lactate dehydrogenase

Answer

Acetyl-CoA carboxylase

Question 2

During the light-dependent reactions, what is the role of plastoquinone (PQ)?

Accepted Answer

It shuttles electrons from PSII to the cytochrome b6f complex

Answer

It accepts electrons from NADPH

Answer

It donates electrons to P700

Answer

It splits water molecules

Question 3

In the citric acid cycle, which step directly produces GTP (or ATP)?

Accepted Answer

Succinyl-CoA → succinate

Answer

Isocitrate → α-ketoglutarate

Answer

Malate → oxaloacetate

Answer

Citrate → isocitrate

Question 4

What is the primary function of the oxygen-evolving complex (OEC) in photosynthesis?

Accepted Answer

Splitting water to release O2 and replenish electrons to PSII

Answer

Reducing NADP+ to NADPH

Answer

Pumping H+ across the thylakoid membrane

Answer

Absorbing light energy at 700 nm

Question 5

How many carbon atoms enter the citric acid cycle per turn via acetyl-CoA, and how many leave as CO2?

Accepted Answer

2 enter, 2 leave

Answer

2 enter, 1 leaves

Answer

3 enter, 3 leave

Answer

4 enter, 2 leave

Question 6

Which photosynthetic pigment has peak absorption at approximately 700 nm and is the reaction center of Photosystem I?

Accepted Answer

P700 chlorophyll a

Answer

P680 chlorophyll a

Answer

Chlorophyll b

Answer

Beta-carotene

Question 7

During anaerobic fermentation in yeast, what happens to pyruvate?

Accepted Answer

It is decarboxylated to acetaldehyde, then reduced to ethanol

Answer

It is converted to lactate by lactate dehydrogenase

Answer

It enters the citric acid cycle as acetyl-CoA

Answer

It is phosphorylated to form ATP