Question 1

Which of the following best describes the primary benefit of fermentation for microorganisms?

Accepted Answer

It enables ATP production in the absence of oxygen by regenerating NAD$$^+$$ from NADH.

Question 2

During glycolysis, which molecule acts as the primary electron carrier, accepting electrons and becoming reduced?

Accepted Answer

NAD$$^+$$

Question 3

Which of the following reactions does NOT require an enzyme to proceed?

Accepted Answer

Spontaneous decomposition of hydrogen peroxide ($$2H_2O_2 \rightarrow 2H_2O + O_2$)

Question 4

Which of the following is NOT a likely substrate that can enter the glycolytic pathway?

Accepted Answer

Fatty acids

Question 5

In catabolic pathways, what is the primary role of NADH and NADPH?

Accepted Answer

They serve as electron carriers, transferring electrons to the electron transport chain or biosynthetic reactions.

Question 6

Which catabolic pathway is primarily responsible for generating NADPH for biosynthesis?

Accepted Answer

Pentose phosphate pathway

Question 7

Which molecule from carbohydrate catabolism enters directly into the citric acid cycle?

Accepted Answer

Acetyl-CoA

Question 8

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

Accepted Answer

To generate a proton gradient across a membrane for ATP synthesis.

Question 9

Lithotrophy is best defined as:

Accepted Answer

The use of inorganic compounds as electron donors for energy generation.

Question 10

Which carbon skeleton is commonly used by bacteria to synthesize amino acids?

Accepted Answer

Alpha-ketoglutarate ($$\alpha-$$ketoglutarate)

Question 11

When ammonia is incorporated into a Kreb cycle intermediate, which amino acid is primarily formed?

Accepted Answer

Glutamate

Question 12

Which of the following best describes a photoautotroph?

Accepted Answer

An organism that uses light for energy and CO$$_2 as a $$carbon source.

Question 13

Why is phosphorus essential for microbes?

Accepted Answer

It is a key component of nucleic acids and ATP.

Question 14

Which process converts ammonia ($$NH_3) to $$nitrate ($$NO_3$$^-$$) in the nitrogen cycle?

Accepted Answer

Nitrification

Question 15

Which biogeochemical cycle does NOT have an atmospheric component?

Accepted Answer

Phosphorus cycle

Question 16

Which of the following best illustrates competitive inhibition?

Accepted Answer

A molecule resembling the substrate binds to the active site, preventing substrate binding.

Question 17

In the electron transport chain, which molecule acts as the final electron acceptor in aerobic respiration?

Accepted Answer

O$$_2$$

Question 18

During glycolysis, which of the following is produced per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, 2 pyruvate

Question 19

Which of the following best describes mutualism?

Accepted Answer

Both organisms benefit from the relationship.

Question 20

How many net ATP molecules are produced from one molecule of glucose during aerobic respiration?

Accepted Answer

36-38

Microbiology Exam 4 Study Guide – Step-by-Step Guidance

Study Guide - Practice Questions