Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

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

Question 3

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy required for a reaction to occur.

Question 4

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 5

Which of the following best explains why increasing substrate concentration can overcome the effect of a competitive inhibitor?

Accepted Answer

The substrate outcompetes the inhibitor for binding to the active site.

Question 6

Which of the following is NOT a product of the Krebs cycle?

Accepted Answer

$$\mathrm{O_2$}$$

Question 7

What is the main function of the electron transport chain in cellular respiration?

Accepted Answer

To transfer electrons and use the released energy to generate a proton gradient for ATP synthesis.

Question 8

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated by the transfer of a phosphate group directly from a phosphorylated compound to ADP.

Question 9

Which of the following statements about feedback inhibition is correct?

Accepted Answer

The end-product of a pathway allosterically inhibits the first enzyme in the pathway.

Question 10

Which of the following is a correct description of a ribozyme?

Accepted Answer

An RNA molecule that acts as a catalyst and is not used up in the reaction.

Question 11

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

Accepted Answer

2 ATP and 2 NADH

Question 12

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

Accepted Answer

It serves as an electron carrier, accepting electrons during oxidation reactions.

Question 13

Which of the following is true regarding the difference between aerobic and anaerobic respiration?

Accepted Answer

Aerobic respiration uses oxygen as the final electron acceptor, while anaerobic respiration uses an inorganic molecule other than oxygen.

Question 14

Which of the following is a correct example of an oxidation-reduction (redox) reaction?

Accepted Answer

$$\mathrm{NAD^+}$$ gains electrons to become $$\mathrm{NADH}$$, while an organic molecule loses electrons.

Question 15

Which of the following best explains why enzymes are specific for their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that only fits specific substrate molecules.

Question 16

Which of the following factors does NOT directly affect the rate of enzyme-catalyzed reactions?

Accepted Answer

Osmotic pressure

Question 17

Which of the following statements about the denaturation of enzymes is correct?

Accepted Answer

Denaturation involves the loss of the enzyme's three-dimensional structure, resulting in loss of function.

Question 18

Which of the following is a product of lactic acid fermentation?

Accepted Answer

Lactic acid

Question 19

Which of the following best describes the fate of fatty acids during lipid catabolism?

Accepted Answer

They undergo beta-oxidation to form acetyl-CoA, which enters the Krebs cycle.

Question 20

A patient’s bacterial isolate is tested in the laboratory and produces gas and acid from glucose fermentation but does not grow in the presence of oxygen. Which metabolic pathway is most likely active in this organism?

Accepted Answer

Fermentation

Microbial Metabolism: Anabolism, Catabolism, and Energy Production

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