Question 1

Which of the following best describes the main purpose of cellular respiration in eukaryotic cells?

Accepted Answer

To convert the energy stored in glucose into ATP through a controlled series of redox reactions.

Question 2

During glycolysis, ATP is produced by which process?

Accepted Answer

Substrate-level phosphorylation

Question 3

Which of the following equations correctly represents the complete oxidation of glucose during aerobic cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6 O_2$ \rightarrow 6 CO_2$ + 6 H_2O + E$$

Question 4

Why is oxygen considered the preferred final electron acceptor in aerobic respiration?

Accepted Answer

Oxygen is highly electronegative, resulting in a large proton gradient and efficient ATP production.

Question 5

In the absence of oxygen, which process allows cells to continue producing ATP?

Accepted Answer

Fermentation

Question 6

Which enzyme is responsible for the regulation of glycolysis at the first committed step, and how is it regulated?

Accepted Answer

Phosphofructokinase; it is allosterically inhibited by high levels of ATP.

Question 7

What is the main function of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

To create a proton gradient across the inner mitochondrial membrane by transferring electrons through a series of redox reactions.

Question 8

Which of the following statements about ATP synthase is correct?

Accepted Answer

ATP synthase uses the flow of protons (H+) down their gradient to catalyze the formation of ATP from ADP and Pi.

Question 9

A drug that blocks the function of cytochrome c would have which of the following effects on cellular respiration?

Accepted Answer

It would halt electron transport, preventing ATP production by oxidative phosphorylation and leading to cell death.

Question 10

During lactic acid fermentation in muscle cells, what happens to the lactate produced?

Accepted Answer

Most is released into the bloodstream and transported to the liver, where it can be converted back to glucose.

Question 11

Which of the following best explains why fermentation is less efficient than aerobic respiration?

Accepted Answer

Fermentation results in incomplete oxidation of glucose, producing only 2 ATP per glucose molecule.

Question 12

Where does glycolysis occur in eukaryotic cells?

Accepted Answer

Cytoplasm

Question 13

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

Accepted Answer

Oxygen ($$O_2)$$

Question 14

What is the main role of NADH and FADH2 in cellular respiration?

Accepted Answer

They donate electrons to the electron transport chain, driving the production of ATP.

Question 15

Which of the following is a correct description of chemiosmosis?

Accepted Answer

The use of a proton gradient to drive the synthesis of ATP.

Question 16

In prokaryotic cells, where does pyruvate processing occur?

Accepted Answer

Cytosol

Question 17

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

Accepted Answer

It completes the oxidation of glucose to $$CO_2$$ and produces NADH, FADH2, and ATP (or GTP).

Question 18

Why do cells perform cellular respiration in a stepwise manner rather than in a single reaction?

Accepted Answer

To control the release of energy and efficiently capture it as ATP rather than losing it as heat.

Question 19

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

Accepted Answer

Fermentation does not use an electron transport chain, while anaerobic respiration does.

Question 20

A patient is given a drug that inhibits ATP synthase. What is the most likely immediate effect on their cells?

Accepted Answer

ATP production by oxidative phosphorylation would stop, leading to rapid energy depletion.

Cellular Respiration: Mechanisms of Energy Conversion in Cells

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