Question 1

Which of the following best describes the main purpose of cellular respiration in eukaryotic cells?

Accepted Answer

To convert the chemical energy stored in glucose into ATP, which can be used for cellular work.

Question 2

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

Accepted Answer

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

Question 3

Which of the following statements about substrate-level phosphorylation is correct?

Accepted Answer

It involves the direct transfer of a phosphate group from a substrate molecule to ADP to form ATP.

Question 4

What is the final electron acceptor in aerobic cellular respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

Which process occurs in the cytoplasm and does not require oxygen?

Accepted Answer

Glycolysis

Question 6

A patient’s muscle cells are deprived of oxygen during intense exercise. Which pathway allows ATP production to continue under these conditions?

Accepted Answer

Lactic acid fermentation

Question 7

Which of the following best explains why NAD+ regeneration is essential for glycolysis to continue?

Accepted Answer

NAD+ is required to accept electrons during the oxidation of glyceraldehyde-3-phosphate in glycolysis.

Question 8

Which of the following is a correct summary of the products generated from one glucose molecule after the citric acid cycle (Krebs cycle) is complete (including the prep step)?

Accepted Answer

$$8$$ NADH, $$2$$ $$FADH_2$$, $$2$$ ATP, $$6$$ $$CO_2$

Question 9

Which enzyme is allosterically inhibited by high levels of ATP during glycolysis, thus regulating the pathway?

Accepted Answer

Phosphofructokinase

Question 10

In the electron transport chain, what is the main role of the complexes embedded in the inner mitochondrial membrane?

Accepted Answer

To transfer electrons and pump protons ($$H^+) $$into the intermembrane space, creating a proton gradient.

Question 11

Which of the following best describes chemiosmosis in mitochondria?

Accepted Answer

The movement of protons ($$H^+) $$down their electrochemical gradient through ATP synthase, driving the phosphorylation of ADP to ATP.

Question 12

A yeast cell is placed in an anaerobic environment. Which of the following products will accumulate as a result of fermentation?

Accepted Answer

Ethanol and $$CO_2$$

Question 13

Which of the following statements about the citric acid cycle is FALSE?

Accepted Answer

It directly produces the majority of ATP during cellular respiration.

Question 14

Which of the following best explains why oxygen is required for aerobic respiration?

Accepted Answer

Oxygen acts as the final electron acceptor in the electron transport chain, allowing the chain to continue functioning.

Question 15

If a poison blocks the function of ATP synthase, which of the following would you expect to occur?

Accepted Answer

The proton gradient would build up, but ATP production by oxidative phosphorylation would stop.

Question 16

Which of the following is a key regulatory mechanism of the pyruvate dehydrogenase complex (prep step)?

Accepted Answer

It is inhibited by high concentrations of ATP and acetyl-CoA.

Question 17

Which of the following best describes the fate of the carbons from glucose after complete aerobic respiration?

Accepted Answer

They are released as $$CO_2$$ during the citric acid cycle and pyruvate oxidation.

Question 18

A bacterium uses nitrate ($$NO_3$$^-$$) instead of oxygen as the final electron acceptor in its electron transport chain. Which type of respiration is this?

Accepted Answer

Anaerobic respiration

Question 19

Which of the following is a correct sequence of events in aerobic cellular respiration?

Accepted Answer

Glycolysis $$\rightarrow$$ Pyruvate oxidation $$\rightarrow$$ Citric acid cycle $$\rightarrow$$ Electron transport and chemiosmosis

Question 20

A genetic mutation causes a defect in the enzyme that catalyzes the conversion of pyruvate to acetyl-CoA. Which of the following would most likely result?

Accepted Answer

The citric acid cycle would slow down or stop, and less ATP would be produced by oxidative phosphorylation.

Cellular Respiration: Pathways for ATP Production

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