Question 1

Which of the following best describes the fate of pyruvate during anaerobic respiration in human muscle cells?

Accepted Answer

Pyruvate is converted into lactic acid in the cytoplasm.

Question 2

During the citric acid cycle, what is the immediate product when acetyl CoA combines with oxaloacetate?

Accepted Answer

Citrate (citric acid)

Question 3

How many molecules of NADH are produced from one molecule of glucose during the citric acid cycle?

Accepted Answer

6

Question 4

Which coenzyme is responsible for carrying two high-energy electrons and two hydrogen ions during the citric acid cycle?

Accepted Answer

FAD

Question 5

What is the main purpose of the electron transport system in cellular respiration?

Accepted Answer

To generate ATP by oxidative phosphorylation

Question 6

Which equation correctly represents the formation of water at the end of the electron transport system?

Accepted Answer

$$1/2\ \mathrm{O}_2 + 2\mathrm{H}^+ + 2\ e^- \rightarrow \mathrm{H}_2\mathrm{O}$$

Question 7

If a person is fasting and glycogen stores are depleted, which macromolecule will the body primarily use next for ATP production?

Accepted Answer

Fats

Question 8

Which process is responsible for the net gain of 34 ATP molecules during cellular respiration?

Accepted Answer

Oxidative phosphorylation

Question 9

What happens to the NAD+ and FAD coenzymes after they drop off their electrons in the electron transport system?

Accepted Answer

They are recycled and reused in earlier stages of cellular respiration.

Question 10

Which of the following best explains why fats yield more ATP than glycogen when metabolized?

Accepted Answer

Fats have longer carbon chains, providing more acetyl groups for the citric acid cycle.

Question 11

A patient with a mitochondrial disorder cannot efficiently use the electron transport system. Which of the following would most likely occur?

Accepted Answer

Increased production of lactic acid during exercise

Question 12

Which of the following is a waste product of protein catabolism that is excreted in urine?

Accepted Answer

Urea

Question 13

Which step in cellular respiration is responsible for the majority of ATP production?

Accepted Answer

Electron transport system

Question 14

What is the role of ATP synthase in the mitochondria?

Accepted Answer

It catalyzes the synthesis of ATP from ADP and inorganic phosphate as H+ ions flow through it.

Question 15

Which of the following equations represents the synthesis of ATP during oxidative phosphorylation?

Accepted Answer

$$\mathrm{ADP} + \mathrm{Pi} \rightarrow \mathrm{ATP}$$

Question 16

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

Accepted Answer

It produces CO2 as a waste product.

Question 17

Which metabolic pathway is responsible for the burning sensation in muscles during intense exercise?

Accepted Answer

Anaerobic glycolysis

Question 18

What is the net gain of ATP molecules from the complete aerobic catabolism of one glucose molecule, accounting for the cost of shuttling NADH into the mitochondria?

Accepted Answer

36

Question 19

Which of the following best explains why the energy from glucose is released slowly during cellular respiration?

Accepted Answer

To allow for efficient capture and storage of energy as ATP.

Question 20

Which molecule is regenerated at the end of the citric acid cycle to allow the cycle to continue?

Accepted Answer

Oxaloacetate

Cellular Respiration: Citric Acid Cycle & Electron Transport System

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