Question 1

Which molecule directly enters the citric acid cycle after the preparatory step in cellular respiration?

Accepted Answer

Acetyl CoA

Question 2

What is the primary role of NAD+ during the citric acid cycle?

Accepted Answer

To pick up hydrogen ions and electrons, forming NADH

Question 3

During the electron transport system, what is the final electron acceptor?

Accepted Answer

Oxygen ($$O_2)$$

Question 4

Which process produces the greatest number of ATP molecules during cellular respiration?

Accepted Answer

Electron transport system

Question 5

What is the net gain of ATP molecules from the complete aerobic catabolism of one glucose molecule?

Accepted Answer

$$36$$

Question 6

Which waste products are generated during the complete aerobic breakdown of glucose?

Accepted Answer

Carbon dioxide ($$CO_2) $$and water ($$H_2O)$$

Question 7

How do fatty acids contribute to ATP production in the mitochondria?

Accepted Answer

They are converted into acetyl groups that enter the citric acid cycle

Question 8

What happens to the amine group ($$NH_2) $$when proteins are catabolized for energy?

Accepted Answer

It is removed and excreted as urea

Question 9

Which of the following best describes oxidative phosphorylation?

Accepted Answer

ATP synthesis powered by the movement of hydrogen ions through ATP synthase

Question 10

Why does anaerobic respiration result in muscle fatigue and cramping?

Accepted Answer

Because of the accumulation of lactic acid

Question 11

Which coenzyme is reduced to FADH$$_2$$ during the citric acid cycle?

Accepted Answer

FAD

Question 12

If a cell is deprived of oxygen, which stage of cellular respiration is directly inhibited?

Accepted Answer

Electron transport system

Question 13

Which of the following is a direct product of the electron transport system?

Accepted Answer

Water ($$H_2O)$$

Question 14

What is the main reason fats yield more ATP than glycogen when metabolized?

Accepted Answer

Fats contain more carbon-hydrogen bonds for energy extraction

Question 15

Which step in cellular respiration is responsible for the majority of carbon dioxide ($$CO_2) $$production?

Accepted Answer

Citric acid cycle

Question 16

A patient is experiencing muscle fatigue after intense exercise. Which metabolic pathway is most likely responsible for the buildup of lactic acid?

Accepted Answer

Anaerobic glycolysis

Question 17

Which of the following best explains why the citric acid cycle must turn twice for each glucose molecule metabolized?

Accepted Answer

Each glucose produces two pyruvate molecules, which are converted to two acetyl CoA molecules

Question 18

Which process is responsible for recycling NAD+ and FAD for reuse in cellular respiration?

Accepted Answer

Electron transport system

Question 19

What is the main fate of the carbon backbone of amino acids during protein catabolism?

Accepted Answer

It enters the citric acid cycle at various points

Question 20

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

Accepted Answer

$$1/2\ O_2$ + 2H^+ + 2e^- \rightarrow H_2O$$

Cellular Respiration: Citric Acid Cycle & Electron Transport System

Study Guide - Practice Questions