Question 1

Which molecule acts as the primary electron donor in the electron transport chain during aerobic respiration?

Accepted Answer

NADH

Question 2

During glycolysis, what is the net gain of ATP and NADH per molecule of glucose?

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 3

Which of the following best describes the role of FADH2 in cellular respiration?

Accepted Answer

It donates electrons to the electron transport chain at a lower energy level than NADH

Question 4

What is the primary function of the Krebs cycle in cellular metabolism?

Accepted Answer

To generate high-energy electron carriers (NADH and FADH2)

Question 5

Which molecule enters the Krebs cycle after glycolysis and pyruvate oxidation?

Accepted Answer

Acetyl-CoA

Question 6

In the electron transport chain, what is the final electron acceptor in aerobic respiration?

Accepted Answer

Oxygen

Question 7

How many NADH molecules are produced per glucose molecule during the Krebs cycle?

Accepted Answer

$$6$$ NADH

Question 8

Which of the following reactions is an example of substrate-level phosphorylation?

Accepted Answer

ATP production during glycolysis

Question 9

During fermentation, which molecule acts as the final electron acceptor?

Accepted Answer

An organic molecule such as pyruvate

Question 10

Which process directly produces the most ATP per glucose molecule in aerobic respiration?

Accepted Answer

Electron transport chain and oxidative phosphorylation

Question 11

What is the total number of ATP molecules produced from one glucose molecule after glycolysis, pyruvate oxidation, and the Krebs cycle (excluding the electron transport chain)?

Accepted Answer

$$4$$ ATP

Question 12

Which of the following statements about NAD+ is correct?

Accepted Answer

NAD+ is reduced to NADH during glycolysis and the Krebs cycle

Question 13

A patient is diagnosed with a mitochondrial disorder that impairs the electron transport chain. Which of the following would most likely be observed?

Accepted Answer

Decreased ATP production and increased reliance on glycolysis

Question 14

Which of the following best explains why FADH2 yields fewer ATP molecules than NADH during oxidative phosphorylation?

Accepted Answer

FADH2 donates electrons at a later point in the electron transport chain, bypassing some proton pumps

Question 15

Which of the following is NOT a product of the Krebs cycle per turn?

Accepted Answer

Glucose

Question 16

What is the main purpose of oxidative phosphorylation in cellular respiration?

Accepted Answer

To generate ATP using the energy from electrons transferred through the electron transport chain

Question 17

Which phase of glycolysis is responsible for the net production of ATP and NADH?

Accepted Answer

Energy payoff phase

Question 18

If a cell is deprived of oxygen, which process will continue to produce ATP?

Accepted Answer

Glycolysis

Question 19

Which of the following best describes the fate of pyruvate in anaerobic conditions in muscle cells?

Accepted Answer

It is reduced to lactate

Question 20

A researcher measures the ATP yield from one glucose molecule in a prokaryotic cell. Which of the following is true compared to a eukaryotic cell?

Accepted Answer

Prokaryotic cells yield slightly more ATP because they do not lose energy transporting NADH into mitochondria

Microbial Metabolism: Catabolism, Electron Carriers, and Energy Production

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