Question 1

Which of the following best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Energy can be transformed from one form to another, but cannot be created or destroyed.

Question 2

A metabolic pathway that releases energy by breaking down complex molecules into simpler compounds is called:

Accepted Answer

Catabolic pathway

Question 3

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

Accepted Answer

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

Question 4

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy barrier, speeding up reactions.

Question 5

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site and blocking substrate binding.

Question 6

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP hydrolysis releases energy that can be coupled to endergonic reactions.

Question 7

If the temperature of an enzyme-catalyzed reaction is increased beyond the enzyme's optimal temperature, what is the most likely outcome?

Accepted Answer

The enzyme will denature, losing its three-dimensional structure and activity.

Question 8

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

A product of the pathway binds to an enzyme early in the pathway, decreasing its activity.

Question 9

Which of the following best describes the effect of a non-competitive inhibitor on enzyme activity?

Accepted Answer

It binds to an allosteric site, changing the enzyme's shape and reducing activity.

Question 10

A reaction has a $$\Delta G of -30 kJ/$$mol. Which of the following statements is TRUE about this reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 11

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction that is currently below its point of saturation?

Accepted Answer

Increasing substrate concentration.

Question 12

Which of the following is NOT a way that enzymes lower activation energy?

Accepted Answer

Changing the overall free energy ($$\Delta G) of $$the reaction.

Question 13

Which of the following best describes the role of allosteric sites in enzyme regulation?

Accepted Answer

They are sites where regulatory molecules bind, changing enzyme activity.

Question 14

A cell needs to synthesize a molecule through an endergonic reaction. Which of the following strategies would the cell most likely use?

Accepted Answer

Couple the endergonic reaction with the hydrolysis of ATP.

Question 15

Which of the following is a correct statement about the Second Law of Thermodynamics in biological systems?

Accepted Answer

Every energy transfer increases the entropy of the universe.

Question 16

Which of the following would most likely result from a mutation that changes the shape of an enzyme's active site?

Accepted Answer

The enzyme would lose its specificity for its substrate.

Question 17

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

Accepted Answer

Synthesis of proteins from amino acids.

Question 18

Which of the following best explains why increasing enzyme concentration does not always increase the rate of reaction indefinitely?

Accepted Answer

The reaction rate plateaus when all substrate molecules are bound and converted.

Question 19

Which of the following is a real-world example of a competitive inhibitor?

Accepted Answer

Methanol acting as a competitive inhibitor of alcohol dehydrogenase.

Question 20

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

Accepted Answer

Each enzyme has an optimal pH, and activity decreases above or below this value.

Introduction to Metabolism and Enzyme Function

Study Guide - Practice Questions