$$\Delta G = G_{\text{products}} - G_{\text{reactants}}$$

Question 1

Which of the following best describes the difference between potential energy and kinetic energy in biological systems?

Accepted Answer

Potential energy is stored energy due to an object's position or structure, while kinetic energy is the energy of motion.

Question 2

A bear running in the wild converts the chemical energy from food into which two main forms of energy, as shown in the provided images?

Accepted Answer

Kinetic energy and thermal energy (heat)

Question 3

According to the first law of thermodynamics, which of the following statements is correct?

Accepted Answer

Energy can be transferred or transformed, but not created or destroyed.

Question 4

Which scenario best illustrates the second law of thermodynamics as it applies to biological systems?

Accepted Answer

A bear releases heat and small molecules as it runs, increasing the disorder of its surroundings.

Question 5

Which of the following equations correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

$$\Delta G = G_{	ext{products}} - G_{	ext{reactants}}$$

Question 6

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases free energy and occurs spontaneously ($$\Delta G \u003c 0)$$

Question 7

Which process is most likely to be catalyzed by a catabolic enzyme?

Accepted Answer

Hydrolysis of sucrose into glucose and fructose

Question 8

What is the primary function of enzymes in biological reactions?

Accepted Answer

To lower the activation energy ($$E_A) $$required for a reaction to proceed

Question 9

Which of the following statements about enzyme specificity is correct?

Accepted Answer

Enzyme specificity results from the fit between the shape of the active site and the substrate.

Question 10

Which model best explains how enzymes and substrates interact during catalysis?

Accepted Answer

Induced fit model, where the active site changes shape to fit the substrate

Question 11

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and increasing the apparent $$K_m$$

Question 12

Which of the following statements about non-competitive (allosteric) inhibition is true?

Accepted Answer

It lowers $$V_{max}$$ without affecting $$K_m.$$

Question 13

Which of the following best describes feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of the pathway inhibits an enzyme that acts early in the pathway.

Question 14

Which of the following statements about ATP hydrolysis is correct?

Accepted Answer

ATP hydrolysis is an exergonic reaction that releases energy for cellular work.

Question 15

Which of the following best explains why enzymes are not consumed in the reactions they catalyze?

Accepted Answer

Enzymes emerge unchanged after the reaction and can catalyze additional reactions.

Question 16

A low $$K_m$$ value for an enzyme indicates:

Accepted Answer

High affinity for its substrate

Question 17

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

Accepted Answer

Synthesis of a protein from amino acids

Question 18

Which of the following regulatory mechanisms is irreversible?

Accepted Answer

Proteolytic activation

Question 19

What is the role of cofactors in enzyme activity?

Accepted Answer

They are nonprotein molecules that help enzymes become active.

Question 20

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

Accepted Answer

Extreme temperatures can denature enzymes, reducing their activity.

Introduction to Metabolism: Energy, Thermodynamics, and Enzyme Function

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