Q: Which of the following best describes the overall chemical equation for aerobic cellular respiration in eukaryotic cells?

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy (ATP + heat)}$$

Question 1

Which of the following best describes the overall chemical equation for aerobic cellular respiration in eukaryotic cells?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{Energy (ATP + heat)}$$

Question 2

During glycolysis, what is the net gain of ATP molecules per molecule of glucose, and by what mechanism are they produced?

Accepted Answer

2 ATP by substrate-level phosphorylation

Question 3

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

Accepted Answer

O$$_2$$

Question 4

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

Accepted Answer

Fermentation

Question 5

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 6

What is the role of NAD$$^+ in $$cellular respiration?

Accepted Answer

It functions as an electron carrier, accepting electrons during redox reactions.

Question 7

Which stage of cellular respiration produces the greatest amount of ATP?

Accepted Answer

Oxidative phosphorylation

Question 8

During chemiosmosis, how is ATP synthesized?

Accepted Answer

By the movement of H$$^+$$ ions down their concentration gradient through ATP synthase

Question 9

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

Accepted Answer

Both use glycolysis, but fermentation produces 2 ATP per glucose while aerobic respiration can produce up to 32 ATP.

Question 10

Which process is responsible for the conversion of pyruvate to acetyl CoA before entering the citric acid cycle?

Accepted Answer

Pyruvate dehydrogenase catalyzes the oxidation of pyruvate, reduction of NAD$$^+$$, and combination with coenzyme A.

Question 11

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

Accepted Answer

It is reduced directly by NADH to form lactate.

Question 12

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

Accepted Answer

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

Question 13

What is the main function of the citric acid cycle in cellular respiration?

Accepted Answer

To oxidize acetyl CoA, generating NADH, FADH$$_2$$, and ATP

Question 14

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

Accepted Answer

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

Question 15

Which of the following is NOT a reason why the exact number of ATP molecules produced from one glucose molecule during cellular respiration is uncertain?

Accepted Answer

All ATP is produced only by substrate-level phosphorylation.

Question 16

Which of the following organisms is most likely to be an obligate anaerobe?

Accepted Answer

A bacterium that dies in the presence of oxygen and relies solely on fermentation

Question 17

What is the evolutionary significance of glycolysis?

Accepted Answer

It is the most widespread metabolic pathway and likely originated in early prokaryotes before oxygen accumulated in the atmosphere.

Question 18

Which feedback mechanism is most commonly used to regulate cellular respiration?

Accepted Answer

Feedback inhibition

Question 19

A patient is diagnosed with a genetic defect that impairs the function of ATP synthase in mitochondria. Which process would be most directly affected?

Accepted Answer

Chemiosmotic synthesis of ATP during oxidative phosphorylation

Question 20

Which of the following is a real-world application of fermentation?

Accepted Answer

Making cheese and yogurt using lactic acid fermentation by bacteria

Cellular Respiration and Fermentation: Catabolic Pathways in Biology

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