Question 1

Which of the following best describes the difference between catabolic and anabolic processes in cells?

Accepted Answer

Catabolic processes break down complex molecules into simpler ones, releasing energy, while anabolic processes build complex molecules from simpler ones, requiring energy input.

Question 2

A reaction has $$\Delta G = +334 kJ/$$mol. Which of the following statements is correct about this reaction?

Accepted Answer

It is endergonic and absorbs energy.

Question 3

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

Accepted Answer

Kinetic energy is the energy of motion, such as molecules moving, while potential energy is stored energy, such as in chemical bonds.

Question 4

Which of the following statements about energy flow in ecosystems is correct according to the first law of thermodynamics?

Accepted Answer

Energy is transformed from one form to another but is neither created nor destroyed.

Question 5

Which molecule contains more free energy: ATP or glucose? Why?

Accepted Answer

Glucose, because it contains more chemical bonds and can be broken down to produce more ATP.

Question 6

What is the role of activation energy ($$E_a) in a $$chemical reaction, and how do enzymes affect it?

Accepted Answer

Activation energy is the energy required to start a reaction; enzymes lower $$E_a to $$increase reaction rate.

Question 7

After an enzyme catalyzes a reaction, what happens to the enzyme?

Accepted Answer

It is released unchanged and can catalyze the same reaction again.

Question 8

Which of the following environmental variables can affect enzyme activity?

Accepted Answer

Temperature, pH, and the presence of inhibitors or cofactors.

Question 9

Which of the following best describes the difference between oxidized and reduced molecules?

Accepted Answer

Oxidized molecules have lost electrons, while reduced molecules have gained electrons.

Question 10

Which of the following is NOT one of the four main ways energy consumed by an organism is used?

Accepted Answer

Photosynthesis

Question 11

A scientist adds a noncompetitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect?

Accepted Answer

The inhibitor binds to a site other than the active site, changing the enzyme's shape and reducing its activity.

Question 12

Which of the following best describes the active site of an enzyme?

Accepted Answer

The region where the substrate binds and the reaction occurs.

Question 13

A patient is diagnosed with a genetic disorder that prevents the production of a necessary cofactor for a key metabolic enzyme. What is the most likely consequence?

Accepted Answer

The enzyme will be unable to catalyze its reaction efficiently, leading to metabolic problems.

Question 14

Which of the following reactions is most likely to be spontaneous?

Accepted Answer

A reaction with $$\Delta G = -30 kJ/$$mol

Question 15

Which of the following is an example of an exergonic reaction in living organisms?

Accepted Answer

Hydrolysis of ATP to ADP and inorganic phosphate

Question 16

A cell needs to move ions against their concentration gradient. Which type of reaction is required, and what is the sign of $$\Delta G$$?

Accepted Answer

Endergonic reaction; $$\Delta G \u003e 0$$

Question 17

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

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrates.

Question 18

Which of the following scenarios best illustrates the application of the first law of thermodynamics in a biological context?

Accepted Answer

A muscle cell converts chemical energy from glucose into kinetic energy for movement.

Question 19

Which of the following statements about enzyme inhibitors is correct?

Accepted Answer

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

Question 20

A researcher observes that an enzyme-catalyzed reaction proceeds much faster at 37°C than at 10°C, but the reaction rate drops sharply at 60°C. What is the most likely explanation?

Accepted Answer

The enzyme denatures at high temperatures, losing its functional shape.

Chapter 8 Study Guide – Bio 101: Energy, Enzymes, and Metabolism

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