Q: Which of the following is a correct summary equation for glycolysis?

$$\text{glucose} + 2\ NAD^+ + 2\ ADP + 2\ P_i \rightarrow 2\ pyruvate + 2\ NADH + 2\ H^+ + 2\ ATP$$

Question 1

Which of the following best describes the difference between anabolic and catabolic pathways in cellular metabolism?

Accepted Answer

Anabolic pathways build cellular components and require energy, while catabolic pathways break down molecules and release energy.

Question 2

Which of the following statements about ATP is correct?

Accepted Answer

ATP contains two phosphoanhydride bonds and one phosphoester bond.

Question 3

Why is the hydrolysis of ATP to ADP and $$P_i$$ highly exergonic?

Accepted Answer

Because of charge repulsion, resonance stabilization of products, and increased entropy.

Question 4

Given the equation $$\Delta G' = \Delta G^\circ' + RT \ln \frac{[ADP][P_i]}{[ATP]}$$, what happens to $$\Delta G' if $$the cellular ATP/ADP ratio increases?

Accepted Answer

$$\Delta G'$$ becomes more negative.

Question 5

Which of the following compounds can directly phosphorylate ADP to form ATP under standard conditions?

Accepted Answer

Phosphoenolpyruvate (PEP)

Question 6

In glycolysis, which step is responsible for the net production of NADH?

Accepted Answer

Gly-6: Oxidation of glyceraldehyde-3-phosphate

Question 7

Which of the following best explains why ATP and ADP are considered higher-energy compounds than AMP?

Accepted Answer

ATP and ADP have more phosphoanhydride bonds, which release more free energy upon hydrolysis.

Question 8

Which of the following is a correct summary equation for glycolysis?

Accepted Answer

$$	ext{glucose} + 2\ NAD^+ + 2\ ADP + 2\ P_i ightarrow 2\ pyruvate + 2\ NADH + 2\ H^+ + 2\ ATP$$

Question 9

Which of the following statements about NAD+ is correct?

Accepted Answer

NAD+ is a coenzyme that acts as an electron acceptor and is reduced to NADH.

Question 10

A facultative organism is placed in an anaerobic environment. Which metabolic pathway will it primarily use to generate ATP?

Accepted Answer

Glycolysis followed by fermentation

Question 11

Which of the following best explains why the glycolytic pathway is considered highly conserved?

Accepted Answer

It is present in virtually all cells and is essential for energy extraction from glucose.

Question 12

Which of the following is NOT a reason why ATP hydrolysis is highly exergonic?

Accepted Answer

Decreased entropy of the products

Question 13

During the oxidation of ethanol to acetaldehyde, which of the following occurs?

Accepted Answer

Ethanol loses hydrogen atoms and is oxidized.

Question 14

Which of the following best describes the role of coenzymes such as NAD+ in cellular metabolism?

Accepted Answer

They function with enzymes to carry electrons and are recycled in the cell.

Question 15

Which of the following statements about the energy yield of glucose catabolism is correct?

Accepted Answer

Complete oxidation of glucose yields $$\Delta G^\circ' = -686$$ kcal/mol, but cells cannot capture all this energy as ATP.

Question 16

Which of the following is a real-life example of a catabolic pathway?

Accepted Answer

Hydrolysis of glucose during glycolysis

Question 17

Which of the following best explains why ATP can phosphorylate glucose but not pyruvate under standard conditions?

Accepted Answer

ATP has a higher standard free energy of hydrolysis than glucose-6-phosphate but lower than pyruvate.

Question 18

Which of the following is a correct description of the fate of electrons removed during glycolysis in the absence of oxygen?

Accepted Answer

They are returned to an organic molecule during fermentation.

Question 19

Which of the following best describes the role of ATP in cellular energy metabolism?

Accepted Answer

ATP serves as the primary energy currency, coupling catabolic and anabolic processes.

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

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