$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + P_i + \text{energy}$$

Question 1

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP couples exergonic and endergonic reactions by transferring a phosphate group.

Question 2

What is released when the terminal phosphate bond of ATP is hydrolyzed?

Accepted Answer

Energy and inorganic phosphate ($$P_i)$$

Question 3

Which of the following equations correctly represents the hydrolysis of ATP?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + P_i + 	ext{energy}$$

Question 4

A scientist adds a chemical to a reaction that binds to the active site of an enzyme, preventing substrate binding. What type of inhibitor is this?

Accepted Answer

Competitive inhibitor

Question 5

Which of the following is NOT a way that enzymes lower activation energy ($$E_A$$)?

Accepted Answer

Increasing the overall change in free energy ($$\Delta G) of $$the reaction

Question 6

Which statement about enzyme specificity is correct?

Accepted Answer

The active site of an enzyme binds only specific substrates due to its unique shape.

Question 7

A metabolic pathway is regulated by feedback inhibition. What is the most likely effect if the end product accumulates?

Accepted Answer

The pathway will shut down as the end product inhibits an early enzyme.

Question 8

Which of the following best explains why an investment of activation energy is necessary to initiate a spontaneous reaction?

Accepted Answer

Activation energy is needed to break existing bonds before new bonds can form.

Question 9

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

Accepted Answer

Vitamin B$$_6$$

Question 10

A mutation causes an enzyme to lose its ability to bind an allosteric inhibitor. What is the most likely consequence?

Accepted Answer

The enzyme will not be regulated by feedback inhibition and may overproduce product.

Question 11

Which of the following best describes the effect of temperature on enzyme activity?

Accepted Answer

Each enzyme has an optimal temperature, above or below which activity decreases.

Question 12

Which of the following statements about allosteric regulation is true?

Accepted Answer

Allosteric regulation can either inhibit or stimulate enzyme activity.

Question 13

Which of the following is a real-life example of enzyme inhibition?

Accepted Answer

Antibiotics inhibiting bacterial enzymes

Question 14

Which of the following best explains why ATP is considered a renewable resource in cells?

Accepted Answer

ATP is regenerated from ADP and inorganic phosphate using energy from catabolic reactions.

Question 15

Which of the following is NOT a function of ATP in the cell?

Accepted Answer

Acting as a catalyst for all metabolic reactions

Question 16

A patient is given a drug that acts as a noncompetitive inhibitor of a key metabolic enzyme. What is the most likely effect on the enzyme's activity?

Accepted Answer

The enzyme will change shape, reducing its ability to bind substrate.

Question 17

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

Accepted Answer

The enzyme changes shape slightly to better fit the substrate upon binding.

Question 18

Which of the following statements about the localization of enzymes within eukaryotic cells is correct?

Accepted Answer

Some enzymes are localized to specific organelles, such as mitochondria for cellular respiration.

Question 19

Which of the following best describes cooperativity in enzyme regulation?

Accepted Answer

A substrate binding to one active site increases the activity at other active sites.

Question 20

Which of the following is true regarding the change in free energy ($$\Delta G) in an $$enzyme-catalyzed reaction?

Accepted Answer

Enzymes do not affect the $$\Delta G of a $$reaction.

ATP and Enzyme Function in Cellular Metabolism

Study Guide - Practice Questions