Question 1

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

Accepted Answer

Catabolic reactions provide energy and building blocks for anabolic reactions, which use that energy to synthesize cellular components.

Question 2

According to collision theory, what is required for a chemical reaction to occur between two molecules?

Accepted Answer

The molecules must collide with sufficient energy to disrupt electronic configurations.

Question 3

Which of the following best explains the effect of a catalyst on the activation energy ($$E_a) of a $$reaction?

Accepted Answer

A catalyst decreases the activation energy, allowing the reaction to proceed faster.

Question 4

Which component is required for an enzyme to be fully functional if it is an apoenzyme?

Accepted Answer

A cofactor, which can be either an inorganic ion or an organic coenzyme.

Question 5

A scientist observes that an enzyme's activity increases with temperature up to a point, then rapidly decreases. What is the most likely explanation for the decrease?

Accepted Answer

The enzyme denatures at high temperatures, losing its functional shape.

Question 6

Which type of enzyme inhibition involves the inhibitor binding to a site other than the active site, causing a change in enzyme shape?

Accepted Answer

Noncompetitive inhibition

Question 7

During substrate-level phosphorylation, how is ATP generated?

Accepted Answer

By transferring a phosphate group directly from a phosphorylated intermediate to ADP.

Question 8

In biological oxidation-reduction (redox) reactions, what is typically removed from the substrate?

Accepted Answer

Electrons, often associated with hydrogen atoms

Question 9

Which pathway is an alternative to glycolysis and produces NADPH and pentoses?

Accepted Answer

Pentose phosphate pathway

Question 10

Which of the following is TRUE about the Entner-Doudoroff pathway?

Accepted Answer

It produces NADPH and ATP and does not involve glycolysis.

Question 11

What is the final electron acceptor in aerobic respiration?

Accepted Answer

Molecular oxygen ($$O_2)$$

Question 12

Which process uses an organic molecule as the final electron acceptor and does not require oxygen?

Accepted Answer

Fermentation

Question 13

During the Krebs cycle, what is the main function of NAD+?

Accepted Answer

To accept electrons and become reduced to NADH

Question 14

Which of the following statements about chemiosmosis is correct?

Accepted Answer

Chemiosmosis uses a proton gradient across a membrane to drive ATP synthesis.

Question 15

A bacterium is found to use $$NO_3$$^-$$ as its final electron acceptor in respiration. What type of respiration is this?

Accepted Answer

Anaerobic respiration

Question 16

Which metabolic process is responsible for the breakdown of fatty acids into acetyl-CoA for entry into the Krebs cycle?

Accepted Answer

Beta-oxidation

Question 17

In photosynthesis, what is the role of the light-dependent reactions?

Accepted Answer

To convert light energy into chemical energy in the form of ATP and NADPH

Question 18

Which enzyme is essential for carbon fixation in the Calvin-Benson cycle?

Accepted Answer

Ribulose bisphosphate carboxylase (RuBisCO)

Question 19

Which group of organisms can use light as an energy source and $$CO_2 as a $$carbon source in an oxygenic process?

Accepted Answer

Cyanobacteria

Question 20

A patient’s bacterial infection is treated with sulfanilamide, which acts as a competitive inhibitor. What is the mechanism of action?

Accepted Answer

Sulfanilamide competes with PABA for the active site of the enzyme, preventing folic acid synthesis.

Microbial Metabolism: Catabolic and Anabolic Reactions

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