Question 1

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy, speeding up the reaction without being consumed.

Question 2

A reaction has a $$\Delta G \u003c 0. $$Which of the following statements is true about this reaction?

Accepted Answer

It is an exergonic reaction and releases energy.

Question 3

Which of the following factors does NOT directly affect enzyme activity?

Accepted Answer

Oxygen concentration

Question 4

In the context of enzyme regulation, what is allosteric inhibition?

Accepted Answer

A regulatory molecule binds to a site other than the active site, changing the enzyme's shape and reducing its activity.

Question 5

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The active site of the enzyme has a unique shape that only fits specific substrates (induced fit model).

Question 6

A scientist increases the substrate concentration in an enzymatic reaction, but the reaction rate no longer increases. What is the most likely explanation?

Accepted Answer

The enzyme is saturated; all active sites are occupied.

Question 7

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

Accepted Answer

The end product of a pathway binds to an enzyme that acts early in the pathway, inhibiting its activity.

Question 8

Which statement about the effect of temperature on enzyme activity is correct?

Accepted Answer

Each enzyme has an optimal temperature at which its activity is highest.

Question 9

What is the main difference between competitive and noncompetitive enzyme inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind to a different site on the enzyme.

Question 10

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

Accepted Answer

Catabolic pathways release energy that can be used to drive anabolic pathways.

Question 11

A reaction in which $$\Delta G \u003e 0 is $$best described as:

Accepted Answer

Endergonic and nonspontaneous

Question 12

Which of the following is a correct statement about the effect of pH on enzyme activity?

Accepted Answer

Enzyme activity is highest at the optimal pH, which varies depending on the enzyme.

Question 13

Which of the following is an example of an inorganic cofactor?

Accepted Answer

Zinc ion ($$\mathrm{Zn$$^{2+}$$})$$

Question 14

Which of the following best explains why enzymes do not affect the $$\Delta G of a $$reaction?

Accepted Answer

Enzymes only lower the activation energy, not the overall energy difference between reactants and products.

Question 15

A patient is given a drug that binds covalently to the active site of an enzyme, permanently disabling it. This is an example of:

Accepted Answer

Irreversible inhibition

Question 16

Which of the following best describes the induced fit model of enzyme function?

Accepted Answer

The enzyme changes shape slightly to fit the substrate more tightly after binding.

Question 17

Which of the following is true about the energy changes in an exergonic reaction?

Accepted Answer

The reaction releases energy, and $$\Delta G is $$negative.

Question 18

Which of the following is a correct example of a metabolic pathway?

Accepted Answer

A series of enzyme-catalyzed reactions where the product of one reaction becomes the substrate for the next.

Question 19

Which of the following statements about ATP is correct?

Accepted Answer

ATP is formed from ADP and $$\mathrm{P_i} in an $$endergonic reaction.

Question 20

If a molecule loses an electron or hydrogen atom during a reaction, it has been:

Accepted Answer

Oxidized

Enzyme Function, Regulation, and Metabolic Pathways: Study Notes for General Biology

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