$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{energy (ATP + heat)}$$

Question 1

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

Accepted Answer

NAD+ is reduced to NADH, serving as an electron carrier that transports electrons to the electron transport chain.

Question 2

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

Accepted Answer

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

Question 3

Which of the following statements about chemiosmosis in mitochondria is correct?

Accepted Answer

Chemiosmosis uses the energy from the proton gradient across the inner mitochondrial membrane to drive ATP synthesis via ATP synthase.

Question 4

Brown fat cells are unique because they:

Accepted Answer

Contain mitochondria that generate heat by allowing H$$^+$$ ions to flow freely across the inner mitochondrial membrane, bypassing ATP synthesis.

Question 5

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

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{energy (ATP + heat)}$$

Question 6

A patient is experiencing muscle fatigue after intense exercise. Which metabolic process is most likely occurring in their muscle cells?

Accepted Answer

Lactic acid fermentation, reducing pyruvate to lactate and regenerating NAD$$^+$$

Question 7

Which of the following best explains why obligate anaerobes cannot survive in the presence of oxygen?

Accepted Answer

Oxygen is toxic to obligate anaerobes, disrupting their metabolic processes.

Question 8

During the citric acid cycle, for each Acetyl-CoA molecule entering the cycle, what are the products generated?

Accepted Answer

$$3$$ NADH, $$1$$ FADH$$_2$$, $$2 CO$_2$$, and $$1$$ ATP

Question 9

Which of the following is true regarding substrate-level phosphorylation?

Accepted Answer

It involves the direct transfer of a phosphate group from a substrate to ADP, forming ATP.

Question 10

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

Accepted Answer

Pyruvate is reduced to ethanol and CO$$_2$$, regenerating NAD$$^+.$$

Question 11

Which of the following statements about the electron transport chain (ETC) is correct?

Accepted Answer

Electrons from NADH and FADH$$_2$$ are transferred through a series of protein complexes, ultimately reducing oxygen to water.

Question 12

Facultative anaerobes are organisms that:

Accepted Answer

Can switch between fermentation and oxidative phosphorylation depending on oxygen availability.

Question 13

Which process is responsible for the majority of ATP production during cellular respiration?

Accepted Answer

Oxidative phosphorylation

Question 14

A scientist exposes white fat cells to cold temperatures and observes some cells begin to burn stored fat. What is the most likely explanation?

Accepted Answer

White fat cells convert into beige cells, which increase metabolic activity and burn fat.

Question 15

Which of the following best explains why the energy stored in NADH is not directly usable by the cell?

Accepted Answer

NADH must first donate its electrons to the electron transport chain, which then uses the released energy to produce ATP.

Question 16

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

Accepted Answer

Glycolysis $$\rightarrow$$ Pyruvate oxidation $$\rightarrow$$ Citric acid cycle $$\rightarrow$$ Oxidative phosphorylation

Question 17

Which of the following is NOT a product of the citric acid cycle?

Accepted Answer

Glucose

Question 18

In lactic acid fermentation, which of the following occurs?

Accepted Answer

Pyruvate is reduced to lactate, and NADH is oxidized to NAD$$^+.$$

Question 19

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

Accepted Answer

Oxygen acts as the final electron acceptor in the electron transport chain, forming water.

Question 20

A yeast culture is grown in an anaerobic environment. Which of the following products would you expect to find in the medium?

Accepted Answer

Ethanol and CO$$_2$$

Cellular Respiration: Mechanisms and Pathways

Study Guide - Practice Questions