Question 1

Which of the following best describes an allosteric regulator in enzyme kinetics?

Accepted Answer

A molecule that binds to a site other than the active site, causing a conformational change in the enzyme.

Question 2

Which of the following is an example of a covalent modification that regulates enzyme activity?

Accepted Answer

Phosphorylation of a serine residue.

Question 3

A scientist observes that the addition of molecule X increases the rate of an enzyme-catalyzed reaction, but only when molecule X is present at a site distinct from the active site. What is molecule X most likely acting as?

Accepted Answer

An allosteric activator

Question 4

Which equation best represents the Michaelis-Menten equation for enzyme kinetics?

Accepted Answer

$$v = \frac{V_{max}[S]}{K_m + [S]}$$

Question 5

Which of the following statements about feedback inhibition is correct?

Accepted Answer

The end product of a pathway inhibits the first committed step of the pathway.

Question 6

A mutation in an enzyme prevents it from being phosphorylated. Which regulatory mechanism is most likely affected?

Accepted Answer

Covalent modification

Question 7

Which of the following is a common allosteric activator of phosphofructokinase-1 (PFK-1) in glycolysis?

Accepted Answer

AMP

Question 8

Which of the following best describes the effect of an allosteric inhibitor?

Accepted Answer

It binds to a regulatory site and decreases enzyme activity.

Question 9

Which of the following is NOT a typical effect of covalent modification on enzyme activity?

Accepted Answer

Increasing the enzyme's gene expression

Question 10

A researcher adds a molecule that acts as an allosteric inhibitor to an enzyme reaction. What is the expected effect on the $$V_{max}$$ and $$K_m of $$the enzyme?

Accepted Answer

$$V_{max}$$ decreases, $$K_m$$ unchanged

Question 11

Which of the following best describes the role of a substrate in an enzyme-catalyzed reaction?

Accepted Answer

It is converted into product by the enzyme.

Question 12

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

ATP inhibits phosphofructokinase-1 in glycolysis.

Question 13

Which of the following is most likely to be a product inhibitor in a metabolic pathway?

Accepted Answer

The product of the last enzyme

Question 14

Which of the following statements about enzyme activators is correct?

Accepted Answer

They can increase the enzyme's catalytic efficiency.

Question 15

Which of the following is a likely effect of an allosteric activator on an enzyme's kinetic curve?

Accepted Answer

Shifts the curve to the left, decreasing $$K_m$$

Allosteric Enzyme Regulation and Control Mechanisms

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