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, such as in chemical bonds or membrane gradients, while kinetic energy is the energy of movement that does work.

Question 2

According to the first law of thermodynamics, which equation correctly represents the conservation of energy in a closed system?

Accepted Answer

$$E_{initial} = E_{final}$$

Question 3

A cell couples the hydrolysis of ATP to drive an endergonic reaction. Which statement best explains why this is possible?

Accepted Answer

The hydrolysis of ATP is exergonic, releasing free energy that can be used to power endergonic reactions.

Question 4

Which of the following reactions is most likely to occur spontaneously in a cell?

Accepted Answer

A reaction with $$\Delta G \u003c 0$$

Question 5

Which statement about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy required for a reaction to proceed.

Question 6

A scientist measures the entropy ($$S) of a $$system before and after a chemical reaction. According to the second law of thermodynamics, what should they expect?

Accepted Answer

Entropy will increase, as energy transformations increase disorder.

Question 7

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

Accepted Answer

Dehydration synthesis of proteins from amino acids

Question 8

If a reaction has $$\Delta G = +5$$ kcal/mol, which of the following statements is true?

Accepted Answer

The reaction is endergonic and requires an input of energy.

Question 9

Which of the following best describes the role of competitive inhibitors in enzyme regulation?

Accepted Answer

They bind to the enzyme's active site, preventing substrate binding.

Question 10

A patient is given aspirin to reduce fever and pain. What is the mechanism by which aspirin works?

Accepted Answer

Aspirin acts as a competitive inhibitor of an enzyme involved in swelling, pain, and fever.

Question 11

Which of the following conditions would most likely decrease enzyme activity in a human cell?

Accepted Answer

Extreme salt concentration

Question 12

Which equation correctly represents the hydrolysis of ATP?

Accepted Answer

$$ATP + H_2O \rightarrow ADP + P_i + G$$

Question 13

Which statement about allosteric enzymes is correct?

Accepted Answer

Allosteric enzymes can exist in both active and inactive forms, regulated by binding of inhibitors or activators.

Question 14

Which of the following best explains why biological systems require a constant input of energy?

Accepted Answer

To maintain order and counteract the natural tendency toward increased entropy.

Question 15

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

Accepted Answer

It is reached when the forward and reverse reactions occur at the same rate.

Question 16

Which of the following is NOT a function of enzymes?

Accepted Answer

Being consumed during the reaction

Question 17

Which of the following best describes an exergonic reaction?

Accepted Answer

It releases free energy ($$\Delta G \u003c 0) $$and often proceeds spontaneously.

Question 18

A researcher adds a competitive inhibitor to an enzyme-catalyzed reaction. What is the most likely immediate effect?

Accepted Answer

The substrate can no longer bind to the enzyme's active site.

Question 19

Which of the following is a catabolic reaction?

Accepted Answer

Hydrolysis of proteins into amino acids

Question 20

Which of the following factors does NOT affect enzyme activity?

Accepted Answer

Presence of products

Energy, Chemical Reactions, and Enzyme Function in Cells

Study Guide - Practice Questions

Study Guide - Flashcards