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

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

Question 1

Which of the following statements best explains why the electron transport chain (ETC) is necessary in aerobic cellular respiration?

Accepted Answer

The ETC allows for the controlled release of energy from electrons, preventing an explosive reaction when electrons combine with oxygen.

Question 2

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

Accepted Answer

$$2$$ ATP, $$2$$ NADH, $$2$$ pyruvate

Question 3

Which molecule acts as the final electron acceptor in aerobic cellular respiration, and what is the product formed?

Accepted Answer

Oxygen; water

Question 4

A patient with a mitochondrial disorder cannot efficiently pump protons across the inner mitochondrial membrane. Which process would be most directly affected?

Accepted Answer

Chemiosmosis and ATP synthesis by ATP synthase

Question 5

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

Accepted Answer

It acts as an oxidizing agent, accepting electrons during redox reactions.

Question 6

If a yeast cell is placed in an anaerobic environment, which metabolic pathway will it primarily use to generate ATP, and what byproducts will accumulate?

Accepted Answer

Alcohol fermentation; ethanol and CO$$_2$$

Question 7

Which of the following is a key difference between fermentation and anaerobic respiration?

Accepted Answer

Fermentation uses an organic molecule as the final electron acceptor, while anaerobic respiration uses an inorganic molecule other than oxygen.

Question 8

A muscle cell is rapidly contracting during intense exercise and oxygen becomes scarce. Which process will the cell switch to, and what is the main purpose of this switch?

Accepted Answer

Lactic acid fermentation; to regenerate NAD$$^+$$ for glycolysis

Question 9

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

Accepted Answer

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

Question 10

Which step in cellular respiration produces the greatest amount of ATP per glucose molecule?

Accepted Answer

Oxidative phosphorylation

Question 11

A bacterium living in the human gut uses hydrogen sulfide as its final electron acceptor. Which process is it performing?

Accepted Answer

Anaerobic respiration

Question 12

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

Accepted Answer

Fats have more reduced carbon atoms, allowing for more electrons to be transferred to NAD$$^+$$ and FAD during beta oxidation.

Question 13

Which enzyme catalyzes the conversion of pyruvate to acetyl CoA during cellular respiration?

Accepted Answer

Pyruvate dehydrogenase

Question 14

If a mutation prevents the regeneration of NAD$$^+$$ during fermentation, what would be the immediate consequence for the cell?

Accepted Answer

Glycolysis would stop due to lack of NAD$$^+$$, halting ATP production.

Question 15

Which of the following is a correct sequence of events for the complete aerobic breakdown of glucose?

Accepted Answer

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

Question 16

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

Accepted Answer

It completes the oxidation of acetyl CoA, producing CO$$_2$$, NADH, FADH$$_2$$, and ATP.

Question 17

Which of the following best describes the main function of fermentation in cells?

Accepted Answer

To regenerate NAD$$^+ so $$glycolysis can continue producing ATP in the absence of oxygen.

Question 18

A person is fasting and their body begins to break down stored fats for energy. Which process is primarily responsible for converting fatty acids into molecules that can enter the citric acid cycle?

Accepted Answer

Beta oxidation

Question 19

Which of the following is a similarity between fermentation and cellular respiration?

Accepted Answer

Both use glycolysis to oxidize glucose to pyruvate.

Question 20

Which of the following statements about catabolic and anabolic pathways is correct?

Accepted Answer

Catabolic pathways break down molecules to release energy, while anabolic pathways use energy to build complex molecules.

Cellular Respiration and Fermentation: Key Concepts and Pathways

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