Question 1

Which of the following best describes the difference between catabolism and anabolism in cellular metabolism?

Accepted Answer

Catabolism breaks down molecules to release energy, while anabolism uses energy to synthesize macromolecules.

Question 2

In the redox reaction $$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O}$$, which molecule is oxidized and which is reduced?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} is $$oxidized and $$\mathrm{O_2$} is $$reduced.

Question 3

Which of the following statements about NAD$$^+/$$NADH is correct?

Accepted Answer

NADH acts as an electron donor in redox reactions.

Question 4

Which process directly generates ATP via substrate-level phosphorylation?

Accepted Answer

Glycolysis

Question 5

During glycolysis, which step requires NAD$$^+ as a $$coenzyme?

Accepted Answer

Conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate

Question 6

Which of the following is a key difference between fermentation and respiration?

Accepted Answer

Fermentation generates ATP only by substrate-level phosphorylation, while respiration uses both substrate-level and oxidative phosphorylation.

Question 7

Which enzyme is responsible for the final step of ATP generation in oxidative phosphorylation?

Accepted Answer

ATP synthase

Question 8

A bacterium is growing anaerobically and produces lactic acid as its main fermentation product. Which pathway is it most likely using?

Accepted Answer

Homolactic fermentation

Question 9

Which of the following best explains why glycolysis can occur in both aerobic and anaerobic organisms?

Accepted Answer

Glycolysis does not require oxygen and can regenerate NAD$$^+$$ through fermentation.

Question 10

Which of the following is a short-term energy storage molecule in cells?

Accepted Answer

Adenosine triphosphate (ATP)

Question 11

In the electron transport chain, what is the primary role of cytochromes?

Accepted Answer

To transfer electrons via their iron atom between carriers in the chain

Question 12

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

Accepted Answer

It is used by ATP synthase to generate ATP from ADP and inorganic phosphate.

Question 13

Which of the following is true regarding the products of glycolysis from one molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

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.

Question 15

A mutation in a bacterium prevents the regeneration of NAD$$^+$$ during fermentation. What is the most likely consequence?

Accepted Answer

Glycolysis will stop due to lack of NAD$$^+ as an $$electron acceptor.

Question 16

Which of the following is a correct pairing of enzyme class and example from glycolysis?

Accepted Answer

Dehydrogenase – Glyceraldehyde-3-phosphate dehydrogenase

Question 17

Which of the following best explains why fermentation yields less ATP per glucose than aerobic respiration?

Accepted Answer

Fermentation does not fully oxidize glucose to CO$$_2$$ and does not use oxidative phosphorylation.

Question 18

Which of the following is a product of alcohol fermentation in yeast?

Accepted Answer

Ethanol

Question 19

Which of the following best describes the role of electron carriers such as NAD$$^+$$ and FAD in metabolism?

Accepted Answer

They transfer electrons from catabolic reactions to the electron transport chain.

Question 20

Which of the following is a long-term energy storage molecule in prokaryotes?

Accepted Answer

Glycogen

Microbial Metabolism: Electron Flow and Energy Production

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