Question 1

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

Accepted Answer

Catabolic reactions release energy by breaking down molecules, which is then used by anabolic reactions to build complex molecules.

Question 2

Which of the following is the correct definition of oxidation in biological systems?

Accepted Answer

Loss of electrons

Question 3

A scientist is studying a metabolic pathway in which the end product inhibits an enzyme that acts early in the pathway. This is an example of:

Accepted Answer

Feed-back inhibition

Question 4

Which of the following molecules acts as the main energy currency in all living cells?

Accepted Answer

ATP

Question 5

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy required for a reaction.

Question 6

Which of the following best describes the role of NADH in cellular metabolism?

Accepted Answer

It donates electrons to generate a proton motive force.

Question 7

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 8

Which of the following factors does NOT directly affect the shape of an enzyme's active site?

Accepted Answer

Substrate concentration

Question 9

Which of the following is a correct pairing of a coenzyme and its primary metabolic role?

Accepted Answer

NAD+ – electron carrier in catabolic reactions

Question 10

In prokaryotic cells, where is the proton motive force generated during cellular respiration?

Accepted Answer

Plasma membrane

Question 11

Which of the following best explains why enzyme activity increases with substrate concentration up to a certain point?

Accepted Answer

The enzyme becomes saturated and cannot work any faster.

Question 12

Which of the following is an example of an anabolic reaction?

Accepted Answer

Synthesis of proteins from amino acids

Question 13

A patient is given a sulfa drug to treat a bacterial infection. This drug acts by:

Accepted Answer

Competing with PABA for the active site of an enzyme.

Question 14

Which of the following best describes the difference between NAD+ and NADH?

Accepted Answer

NAD+ is the oxidized form, NADH is the reduced form.

Question 15

Which of the following is NOT a property of enzymes?

Accepted Answer

They are permanently changed during the reaction.

Question 16

Which of the following best describes the role of a cofactor in enzyme function?

Accepted Answer

It is required to make the enzyme functional.

Question 17

Which of the following is the best example of a noncompetitive inhibitor?

Accepted Answer

A molecule that binds to an allosteric site and changes the enzyme's conformation.

Question 18

Which of the following is the correct sequence of stages in aerobic cellular respiration?

Accepted Answer

Glycolysis → Krebs cycle → Electron transport chain

Question 19

Which of the following is the final electron acceptor in aerobic cellular respiration?

Accepted Answer

Oxygen

Question 20

Which of the following best explains why ATP is considered the energy currency of the cell?

Accepted Answer

ATP stores energy in its high-energy phosphate bonds, which can be broken to do cellular work.

Microbial Metabolism: Key Concepts and Pathways

Study Guide - Practice Questions