Question 1

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

NAD+ functions as an electron carrier, accepting electrons and protons to become NADH.

Question 2

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

Accepted Answer

2 ATP and 2 NADH

Question 3

Which of the following equations correctly represents the overall process of cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy$$

Question 4

What is the primary function of the electron transport chain in mitochondria?

Accepted Answer

To pump protons (H+) across the inner mitochondrial membrane, creating a proton gradient

Question 5

Which molecule is the final electron acceptor in aerobic cellular respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 6

In the absence of oxygen, which process allows glycolysis to continue by regenerating NAD+?

Accepted Answer

Fermentation

Question 7

Which of the following is a product of lactic acid fermentation?

Accepted Answer

Lactate

Question 8

A yeast cell is placed in an anaerobic environment. Which end products will accumulate as a result of its metabolism?

Accepted Answer

Ethanol and $$CO_2$$

Question 9

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

Accepted Answer

It produces NADH, FADH2, ATP, and $$CO_2 as $$end products.

Question 10

Which process in cellular respiration produces the greatest amount of ATP?

Accepted Answer

Oxidative phosphorylation

Question 11

A patient is exposed to cyanide, which blocks the transfer of electrons to oxygen in the electron transport chain. What is the most immediate effect on cellular respiration?

Accepted Answer

ATP production by oxidative phosphorylation will cease.

Question 12

Which of the following best explains why fats yield more ATP per gram than carbohydrates?

Accepted Answer

Fats are more reduced and have more high-energy electrons for the electron transport chain.

Question 13

Which of the following is an example of feedback inhibition in cellular respiration?

Accepted Answer

High levels of ATP inhibit an enzyme in glycolysis.

Question 14

Which of the following organisms is an obligate anaerobe?

Accepted Answer

A bacterium that dies in the presence of oxygen

Question 15

In the process of chemiosmosis, what directly drives the synthesis of ATP?

Accepted Answer

The movement of H+ ions down their concentration gradient through ATP synthase

Question 16

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

Accepted Answer

It is reduced to lactate to regenerate NAD+

Question 17

Which of the following statements about glycolysis is FALSE?

Accepted Answer

It requires oxygen to proceed.

Question 18

A facultative anaerobe is placed in an environment with no oxygen but abundant glucose. Which pathway will it primarily use to generate ATP?

Accepted Answer

Fermentation

Question 19

Which of the following is a correct sequence of energy flow during cellular respiration?

Accepted Answer

Glucose $$\rightarrow$$ NADH $$\rightarrow$$ electron transport chain $$\rightarrow$$ proton-motive force $$\rightarrow$$ ATP

Question 20

Which of the following is NOT a reason why the exact number of ATP molecules produced from one glucose molecule during cellular respiration is variable?

Accepted Answer

Glycolysis always produces exactly 4 ATP per glucose.

Cellular Respiration and Fermentation: Mechanisms of Energy Harvest in Cells

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