Q: Which of the following reactions is exergonic?

Hydrolysis of ATP to ADP and inorganic phosphate ($$\text{ATP} \rightarrow \text{ADP} + \text{P}_i)$$

Question 1

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

Accepted Answer

ATP serves as the primary energy carrier, coupling exergonic and endergonic reactions.

Question 2

According to the 2nd Law of Thermodynamics, which statement is correct regarding entropy in biological systems?

Accepted Answer

Biological systems maintain order by increasing entropy elsewhere.

Question 3

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 4

Which equation correctly represents the change in free energy ($$\Delta G) of a $$reaction?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 5

Which of the following is an example of an anabolic pathway?

Accepted Answer

Photosynthesis synthesizing glucose from CO$$_2$$ and H$$_2O.$$

Question 6

If an enzyme-catalyzed reaction is inhibited by a molecule binding to a site other than the active site, this is called:

Accepted Answer

Noncompetitive inhibition

Question 7

Which statement best explains why enzymes lower activation energy?

Accepted Answer

Enzymes provide a favorable microenvironment and stabilize the transition state.

Question 8

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

Accepted Answer

The maximum reaction rate ($$V_{max}) $$decreases, but $$K_m$$ remains unchanged.

Question 9

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme involved early in the pathway.

Question 10

Which of the following is NOT a function of cofactors in enzyme activity?

Accepted Answer

Acting as a competitive inhibitor.

Question 11

Which of the following reactions is exergonic?

Accepted Answer

Hydrolysis of ATP to ADP and inorganic phosphate ($$	ext{ATP} ightarrow 	ext{ADP} + 	ext{P}_i)$$

Question 12

Which term describes the energy required to initiate a chemical reaction?

Accepted Answer

Activation energy

Question 13

A mutation changes the shape of an enzyme's active site. What is the most likely consequence?

Accepted Answer

The enzyme may lose its ability to catalyze the reaction.

Question 14

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 15

Which pathway is most likely to be regulated by feedback inhibition?

Accepted Answer

A biosynthetic pathway producing amino acids.

Question 16

Which statement about enzyme-substrate complexes is correct?

Accepted Answer

The enzyme-substrate complex is a temporary intermediate during catalysis.

Question 17

Which of the following is true about chemical energy in biological systems?

Accepted Answer

Chemical energy is stored in the bonds of molecules such as glucose and ATP.

Question 18

Which of the following statements about catabolic pathways is correct?

Accepted Answer

Catabolic pathways break down complex molecules into simpler ones, releasing energy.

Question 19

A scientist measures the rate of an enzyme-catalyzed reaction and finds that increasing substrate concentration no longer increases the reaction rate. What is the most likely explanation?

Accepted Answer

The enzyme is saturated with substrate and operating at $$V_{max}.$$

Question 20

Which of the following best explains the role of allosteric regulation in enzyme activity?

Accepted Answer

Allosteric regulation involves molecules binding to sites other than the active site, altering enzyme activity.

Energy, Enzymes, and Metabolism: Core Concepts and Mechanisms

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