Question 1

Which of the following best describes the relationship between catabolic and anabolic pathways in microbial metabolism?

Accepted Answer

Catabolic pathways break down complex molecules to release energy, which is then used by anabolic pathways to build macromolecules.

Question 2

Which of the following equations correctly represents the overall reaction for aerobic respiration in prokaryotes?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$ + 6\ O_2$ + 38\ ADP + 38\ P_i \rightarrow 6\ CO_2$ + 6\ H_2O + 38\ ATP}$$

Question 3

Which of the following statements about enzymes is CORRECT?

Accepted Answer

Enzymes lower the activation energy, allowing reactions to occur more rapidly.

Question 4

A competitive inhibitor of an enzyme acts by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 5

Which of the following best explains why high temperatures can decrease enzyme activity?

Accepted Answer

High temperatures denature the enzyme, altering its active site.

Question 6

Which of the following is a correct description of oxidative phosphorylation?

Accepted Answer

ATP is generated using energy derived from the electron transport chain and chemiosmosis.

Question 7

During glycolysis, what is the net gain of ATP and NADH molecules per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH

Question 8

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

NAD+ acts as an electron carrier, accepting electrons during glycolysis and the Krebs cycle.

Question 9

Which of the following is a product of the pentose phosphate pathway that is NOT produced by glycolysis?

Accepted Answer

NADPH

Question 10

In the electron transport chain of aerobic respiration, what is the final electron acceptor?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 11

Which of the following best explains why fermentation is less efficient than aerobic respiration?

Accepted Answer

Fermentation only uses substrate-level phosphorylation and does not utilize the electron transport chain.

Question 12

Which of the following is a correct pairing of enzyme class and reaction type?

Accepted Answer

Transferase: transfer of functional groups

Question 13

A bacterium is found to use $$\mathrm{SO_4$^{2-}} as $$its final electron acceptor in respiration. Which statement is most accurate?

Accepted Answer

It is performing anaerobic respiration.

Question 14

Which of the following is a function of the Calvin-Benson cycle in photosynthetic organisms?

Accepted Answer

Fixation of carbon dioxide into organic molecules

Question 15

Which of the following best describes an amphibolic pathway?

Accepted Answer

A pathway that functions in both catabolism and anabolism.

Question 16

Which of the following is true regarding the effect of substrate concentration on enzyme activity?

Accepted Answer

Enzyme activity increases with substrate concentration until all active sites are saturated.

Question 17

Which of the following is a correct description of feedback inhibition?

Accepted Answer

The end-product of a pathway acts as an allosteric inhibitor of an enzyme early in the pathway.

Question 18

Which of the following is a correct statement about the fate of fatty acids during lipid catabolism?

Accepted Answer

Fatty acids are converted into acetyl-CoA, which enters the Krebs cycle.

Question 19

Which of the following is a distinguishing feature of lactic acid fermentation compared to alcohol fermentation?

Accepted Answer

Lactic acid fermentation reduces pyruvate directly to lactic acid without releasing CO2.

Question 20

Which of the following best describes the role of chemiosmosis in ATP synthesis?

Accepted Answer

Chemiosmosis uses a proton gradient across a membrane to drive ATP synthesis via ATP synthase.

Microbial Metabolism: Pathways, Enzymes, and Energy Production

Study Guide - Practice Questions