Question 1

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

Accepted Answer

Catabolic pathways break larger molecules into smaller products and are exergonic, while anabolic pathways synthesize large molecules from smaller products and are endergonic.

Question 2

Which of the following statements about oxidation-reduction (redox) reactions is correct?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 3

Which of the following is NOT a method by which cells phosphorylate ADP to ATP?

Accepted Answer

Hydrolytic phosphorylation

Question 4

Apoenzymes are inactive unless they are bound to:

Accepted Answer

Nonprotein cofactors such as inorganic ions or coenzymes

Question 5

Which of the following factors does NOT directly affect the rate of enzymatic reactions?

Accepted Answer

The genetic code of the organism

Question 6

Which of the following best explains why competitive inhibitors can be overcome by increasing substrate concentration?

Accepted Answer

Competitive inhibitors bind reversibly to the active site, so more substrate increases the chance of substrate binding instead of the inhibitor.

Question 7

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

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 8

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

Accepted Answer

Glycolysis → Synthesis of Acetyl-CoA → Krebs Cycle → Electron Transport Chain

Question 9

In the electron transport chain, what is the primary function of the proton gradient established across the membrane?

Accepted Answer

To drive the synthesis of ATP via ATP synthase

Question 10

Which of the following is a unique feature of the Entner-Doudoroff (ED) pathway compared to glycolysis (EMP pathway)?

Accepted Answer

It produces both NADH and NADPH.

Question 11

Which of the following statements about fermentation is TRUE?

Accepted Answer

Fermentation regenerates NAD$$^+ by $$transferring electrons to an organic molecule.

Question 12

Which of the following is a product of the Krebs cycle for each molecule of glucose?

Accepted Answer

$$2$$ ATP, $$6$$ NADH, $$2$$ FADH$$_2$$, $$4 CO$_2$$

Question 13

Which of the following best describes the role of NAD$$^+ in $$cellular metabolism?

Accepted Answer

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

Question 14

A bacterium is growing in an environment lacking oxygen but containing nitrate. Which metabolic process is most likely being used for energy production?

Accepted Answer

Anaerobic respiration

Question 15

Which of the following is a correct statement about feedback inhibition in metabolic pathways?

Accepted Answer

It inhibits the first committed enzyme to prevent unnecessary use of precursors and energy.

Question 16

Which of the following is a direct result of beta-oxidation of fatty acids?

Accepted Answer

Formation of acetyl-CoA for entry into the citric acid cycle

Question 17

Which of the following regulatory mechanisms allows cells to control the activity of enzymes after they have been produced?

Accepted Answer

Control of metabolic expression

Question 18

Which of the following statements about amphibolic pathways is correct?

Accepted Answer

They are pathways that can function in both catabolic and anabolic processes.

Question 19

A patient is given sulfanilamide to treat a bacterial infection. This drug acts as a competitive inhibitor of an enzyme in folic acid synthesis. Which of the following best explains how sulfanilamide works?

Accepted Answer

It mimics the substrate PABA and competes for the active site, blocking folic acid synthesis.

Microbial Metabolism: Structured Study Notes for Microbiology Students

Guida di studio - Domande di pratica

Study guide - Flashcard