Question 1

Which of the following best describes metabolism in microbial cells?

Accepted Answer

The sum of all chemical reactions that lead to the energy exchanges required for growth and reproduction.

Question 2

Cells use ATP as an energy currency. Which chemical reaction releases energy from ATP?

Accepted Answer

ATP + H$$_2O$$ $$\rightarrow$$ ADP + Pi + energy

Question 3

Which statement about catabolic and anabolic reactions is correct?

Accepted Answer

Catabolic reactions break down molecules to release energy, while anabolic reactions use energy to build molecules.

Question 4

During a redox reaction, which molecule is oxidized?

Accepted Answer

The molecule that loses electrons.

Question 5

Which electron carrier is primarily involved in glycolysis and the citric acid cycle?

Accepted Answer

NAD$$^+$$

Question 6

A patient is suffering from a vitamin B deficiency. Which metabolic process is most likely to be affected?

Accepted Answer

Electron transport due to lack of NAD$$^+$$ and FAD

Question 7

Which of the following best explains why oxidation and reduction reactions are always coupled?

Accepted Answer

Because electrons cannot exist freely in solution.

Question 8

Which factor does NOT directly influence the rate of enzymatic reactions?

Accepted Answer

Amount of ATP produced by the cell

Question 9

Competitive inhibitors affect enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate access.

Question 10

Which pathway is responsible for the initial breakdown of glucose in most cells?

Accepted Answer

Embden-Meyerhof-Parnas (EMP) pathway (glycolysis)

Question 11

During glycolysis, what is the net ATP yield per glucose molecule?

Accepted Answer

2 ATP

Question 12

Which process occurs in both aerobic and anaerobic respiration after glycolysis?

Accepted Answer

Pyruvate oxidation

Question 13

A mutation causes an enzyme to lose its active site specificity. What is the most likely consequence?

Accepted Answer

The enzyme will no longer bind its substrate efficiently.

Question 14

Which of the following is true about protein structure?

Accepted Answer

Tertiary structure is the overall 3D shape of a single polypeptide.

Question 15

Which statement best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated directly by transferring a phosphate group from a substrate to ADP.

Question 16

In the EMP pathway, which molecule is the final product before entering the citric acid cycle?

Accepted Answer

Pyruvate

Question 17

Which of the following is a function of electron carrier molecules in metabolism?

Accepted Answer

They temporarily store energy released from metabolic redox reactions.

Question 18

A cell is exposed to a noncompetitive inhibitor. What is the expected effect on enzyme activity?

Accepted Answer

The inhibitor binds to an allosteric site, changing the enzyme's shape and reducing activity.

Question 19

Which of the following is NOT a product of glycolysis?

Accepted Answer

CO$$_2$$

Question 20

If a microbe is unable to regenerate NAD$$^+$$ during fermentation, what will happen to glycolysis?

Accepted Answer

Glycolysis will slow down and eventually stop due to lack of NAD$$^+.$$

Microbial Metabolism: Energy, Enzymes, and Catabolic Pathways

Study Guide - Practice Questions