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

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 during glycolysis and the citric acid cycle.

Question 2

During glycolysis, glucose is converted into two molecules of pyruvate. What is the net gain of ATP and NADH per molecule of glucose?

Accepted Answer

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

Question 3

Which process occurs in the absence of oxygen and results in the production of lactic acid in muscle cells?

Accepted Answer

Lactic acid fermentation

Question 4

Which equation correctly represents the overall reaction for aerobic cellular respiration?

Accepted Answer

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

Question 5

Feedback inhibition in cellular respiration is best exemplified by which of the following scenarios?

Accepted Answer

High levels of ATP inhibit phosphofructokinase, slowing glycolysis.

Question 6

Which of the following is NOT a product of fermentation in yeast cells?

Accepted Answer

Lactic acid

Question 7

In the citric acid cycle, which molecule is regenerated at the end of each cycle to combine with acetyl-CoA?

Accepted Answer

Oxaloacetate

Question 8

Which statement best explains why fermentation is necessary in anaerobic conditions?

Accepted Answer

Fermentation allows glycolysis to continue by regenerating NAD+.

Question 9

Which of the following best describes the role of the electron transport chain in cellular respiration?

Accepted Answer

It transfers electrons from NADH and FADH2 to oxygen, creating a proton gradient.

Question 10

A patient is diagnosed with a mitochondrial disorder that impairs the electron transport chain. Which symptom is most likely to occur?

Accepted Answer

Decreased ATP production and increased lactic acid in tissues

Question 11

Which of the following is a major difference between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis stores energy in glucose, while cellular respiration releases energy from glucose.

Question 12

Which of the following best explains why plants can perform both photosynthesis and cellular respiration?

Accepted Answer

Plants have both chloroplasts and mitochondria, allowing them to convert light energy to chemical energy and then use it for cellular work.

Question 13

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

Accepted Answer

Glycolysis → Citric acid cycle → Electron transport chain

Question 14

Which molecule is the final electron acceptor in the electron transport chain of aerobic respiration?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 15

Which of the following statements about ATP production is correct?

Accepted Answer

Most ATP is produced during the electron transport chain via oxidative phosphorylation.

Question 16

A cell is exposed to cyanide, which inhibits cytochrome c oxidase in the electron transport chain. What is the immediate effect?

Accepted Answer

Electron transport halts, and ATP synthesis decreases sharply.

Question 17

Which of the following is a key regulatory enzyme in glycolysis that is inhibited by high levels of ATP?

Accepted Answer

Phosphofructokinase

Question 18

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

The direct transfer of a phosphate group from a substrate to ADP to form ATP.

Question 19

Which of the following is true regarding the fate of carbon atoms from glucose during cellular respiration?

Accepted Answer

All six carbon atoms are released as $$\mathrm{CO_2$}$$ during the citric acid cycle and pyruvate oxidation.

Question 20

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation allows glycolysis to continue in the absence of oxygen by regenerating NAD+.

Cellular Respiration, Fermentation, and Photosynthesis: Key Concepts and Processes

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