Q: Which of the following summarizes the overall reaction for the citric acid cycle per acetyl CoA?

$\text{Acetyl CoA} + 3\text{NAD}^+ + \text{FAD} + \text{ADP} + P_i \rightarrow 2\text{CO}_2 + 3\text{NADH} + \text{FADH}_2 + \text{CoA-SH} + \text{ATP}$

Q: Which of the following is a correct summary of the overall reaction for aerobic respiration of one glucose molecule?

$\text{Glucose} + 10\text{NAD}^+ + 2\text{FAD} + 4\text{ADP} + 4P_i \rightarrow 6\text{CO}_2 + 10\text{NADH} + 2\text{FADH}_2 + 4\text{ATP}$

Question 1

Under anaerobic conditions in human muscle cells, what is the fate of pyruvate produced by glycolysis?

Accepted Answer

It is reduced to lactate by accepting electrons from NADH.

Question 2

Which enzyme catalyzes the conversion of pyruvate to acetyl CoA in the mitochondria?

Accepted Answer

Pyruvate dehydrogenase complex (PDH)

Question 3

During gluconeogenesis, which steps of glycolysis are bypassed due to their irreversibility?

Accepted Answer

Gly-1, Gly-3, and Gly-10

Question 4

Which of the following summarizes the overall reaction for the citric acid cycle per acetyl CoA?

Accepted Answer

$	ext{Acetyl CoA} + 3	ext{NAD}^+ + 	ext{FAD} + 	ext{ADP} + P_i ightarrow 2	ext{CO}_2 + 3	ext{NADH} + 	ext{FADH}_2 + 	ext{CoA-SH} + 	ext{ATP}$

Question 5

Which activated carrier molecules are produced during the citric acid cycle?

Accepted Answer

NADH, FADH$_2$, and GTP

Question 6

In the absence of oxygen, yeast cells convert pyruvate into which products?

Accepted Answer

Ethanol, CO$_2$, and NAD$^+$

Question 7

Which process describes the synthesis of glucose from non-carbohydrate precursors?

Accepted Answer

Gluconeogenesis

Question 8

Why are the Gly-1, Gly-3, and Gly-10 steps of glycolysis not simply reversed during gluconeogenesis?

Accepted Answer

They are thermodynamically irreversible and require bypass reactions.

Question 9

Which of the following is a correct summary of the overall reaction for aerobic respiration of one glucose molecule?

Accepted Answer

$	ext{Glucose} + 10	ext{NAD}^+ + 2	ext{FAD} + 4	ext{ADP} + 4P_i ightarrow 6	ext{CO}_2 + 10	ext{NADH} + 2	ext{FADH}_2 + 4	ext{ATP}$

Question 10

Which of the following statements about electron transport in mitochondria is correct?

Accepted Answer

Electrons from NADH and FADH$_2$ are transferred to oxygen via a series of membrane-bound carriers.

Question 11

Which metabolic pathway is responsible for the breakdown of fatty acids into acetyl CoA units?

Accepted Answer

Beta-oxidation

Question 12

What is the main purpose of fermentation in cells under anaerobic conditions?

Accepted Answer

To regenerate NAD$^+$ for glycolysis to continue

Question 13

Which of the following is NOT a product of the citric acid cycle per acetyl CoA?

Accepted Answer

Lactate

Question 14

During protein catabolism, what is the fate of amino acids after proteolysis?

Accepted Answer

They are converted into intermediates of glycolysis, pyruvate, or citric acid cycle.

Question 15

Which enzyme is responsible for hydrolyzing internal peptide bonds during protein digestion?

Accepted Answer

Endopeptidase

Question 16

Which of the following best explains why NADH and FADH$_2$ are important in cellular respiration?

Accepted Answer

They store energy that is later used to drive ATP synthesis via the electron transport chain.

Question 17

Which of the following is a correct description of the role of the electron transport chain (ETC) in mitochondria?

Accepted Answer

It pumps protons across the inner mitochondrial membrane to create an electrochemical gradient.

Question 18

Which of the following is a common starting material for gluconeogenesis?

Accepted Answer

Lactate

Question 19

A patient with a genetic defect in the pyruvate dehydrogenase complex (PDH) would most likely have problems with which metabolic process?

Accepted Answer

Conversion of pyruvate to acetyl CoA and entry into the citric acid cycle

Cellular Respiration, Fermentation, and Gluconeogenesis: Key Pathways in Cell Metabolism

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