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

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2 \rightarrow 6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} + \text{energy (ATP + heat)}$$

Question 1

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

Accepted Answer

To break down glucose and generate ATP for cellular work

Question 2

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

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2 ightarrow 6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} + 	ext{energy (ATP + heat)}$$

Question 3

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

Accepted Answer

2 ATP and 2 NADH

Question 4

Which of the following statements about redox reactions in cellular respiration is correct?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 5

What is the primary role of NAD+ in cellular respiration?

Accepted Answer

To carry electrons from glycolysis and the citric acid cycle to the electron transport chain

Question 6

Where does the citric acid cycle take place in eukaryotic cells?

Accepted Answer

In the mitochondrial matrix

Question 7

Which process produces the most ATP during cellular respiration?

Accepted Answer

Oxidative phosphorylation

Question 8

What is the main difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group to ADP from a substrate, while oxidative phosphorylation uses a proton gradient to drive ATP synthesis.

Question 9

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

Accepted Answer

Oxygen ($$\mathrm{O}_2)$$

Question 10

Which of the following best explains why ATP synthase is considered a molecular rotary motor?

Accepted Answer

It rotates as protons flow through it, catalyzing the conversion of ADP and phosphate to ATP.

Question 11

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation regenerates NAD+ by transferring electrons to pyruvate or its derivatives.

Question 12

In lactic acid fermentation, what is the fate of pyruvate?

Accepted Answer

It is reduced to lactate by NADH.

Question 13

Which of the following is a correct comparison between aerobic respiration and fermentation?

Accepted Answer

Aerobic respiration uses oxygen as the final electron acceptor, while fermentation uses an organic molecule.

Question 14

Which enzyme is a key regulatory point in glycolysis and is subject to feedback inhibition by ATP?

Accepted Answer

Phosphofructokinase

Question 15

A patient is diagnosed with a mitochondrial disorder that impairs the electron transport chain. Which of the following would most likely be observed in this patient’s cells?

Accepted Answer

Decreased proton gradient across the inner mitochondrial membrane

Question 16

Which of the following food molecules yields the most ATP per gram when oxidized in cellular respiration?

Accepted Answer

Fats

Question 17

Why is it not possible to state an exact number of ATP molecules generated by the oxidation of one molecule of glucose in cellular respiration?

Accepted Answer

Because the efficiency of oxidative phosphorylation and the use of the proton gradient can vary

Question 18

Which of the following best describes the role of the proton-motive force in cellular respiration?

Accepted Answer

It drives the synthesis of ATP by ATP synthase as protons flow back into the mitochondrial matrix.

Question 19

Which of the following is a product of the citric acid cycle for each acetyl CoA molecule entering the cycle?

Accepted Answer

1 ATP, 3 NADH, 1 FADH2, 2 CO2

Question 20

A muscle cell is working hard during intense exercise and oxygen is limited. Which pathway will the cell primarily use to generate ATP?

Accepted Answer

Lactic acid fermentation

Cellular Respiration and Fermentation: Energy Production in Cells

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