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

Question 1

Which of the following best represents the overall equation for cellular respiration, as shown in the image?

Accepted Answer

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

Question 2

In the overall equation for cellular respiration, which molecule is oxidized and which is reduced?

Accepted Answer

Glucose is oxidized; oxygen is reduced.

Question 3

Which stage of cellular respiration produces the most ATP, and by what process is this ATP generated?

Accepted Answer

Oxidative phosphorylation; by chemiosmosis

Question 4

What is the role of oxygen in the electron transport chain during cellular respiration?

Accepted Answer

It acts as the final electron acceptor, forming water.

Question 5

During glycolysis, what are the net products per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

Question 6

Which of the following statements about substrate-level phosphorylation is correct?

Accepted Answer

It involves the direct transfer of a phosphate group to ADP from an intermediate substrate.

Question 7

Which process is responsible for the majority of carbon dioxide produced during cellular respiration?

Accepted Answer

Citric acid cycle

Question 8

What is the main function of NAD+ and FAD in cellular respiration?

Accepted Answer

They act as electron carriers, transporting electrons to the electron transport chain.

Question 9

Which of the following best describes chemiosmosis in mitochondria?

Accepted Answer

The movement of protons down their concentration gradient through ATP synthase to generate ATP.

Question 10

Why is glycolysis considered an 'ancient' metabolic pathway?

Accepted Answer

It occurs in the cytosol and does not require oxygen or membrane-bound organelles.

Question 11

Which of the following statements about fermentation is true?

Accepted Answer

Fermentation regenerates NAD+ so glycolysis can continue in the absence of oxygen.

Question 12

What is the main difference between obligate anaerobes and facultative anaerobes?

Accepted Answer

Obligate anaerobes cannot survive in the presence of oxygen, while facultative anaerobes can use oxygen if it is available.

Question 13

Which of the following best explains why fats produce more ATP per gram than carbohydrates?

Accepted Answer

Fats have more hydrogen atoms, providing more electrons for the electron transport chain.

Question 14

During strenuous exercise, human muscle cells switch to lactic acid fermentation. What happens to the lactate produced?

Accepted Answer

It is transported to the liver and converted back to glucose.

Question 15

Which of the following is a correct description of beta oxidation?

Accepted Answer

The process by which fatty acids are broken down to generate acetyl-CoA, NADH, and FADH2.

Question 16

Which of the following best describes the efficiency of cellular respiration in converting the energy in glucose to ATP?

Accepted Answer

About 34% of the energy in glucose is transferred to ATP; the rest is lost as heat.

Question 17

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

Accepted Answer

4 NADH

Question 18

Which process is responsible for regenerating NAD+ in the absence of oxygen?

Accepted Answer

Fermentation

Question 19

What is the main reason why the exact number of ATP molecules produced per glucose during cellular respiration is not known?

Accepted Answer

The processes are not directly coupled and the proton-motive force is used for other work.

Question 20

Which of the following best explains why feedback inhibition is important in cellular respiration?

Accepted Answer

It prevents the overproduction of ATP by inhibiting key enzymes when ATP levels are high.

CHP9

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