Question 1

Which statement best describes the role of enzymes in metabolic pathways?

Accepted Answer

Enzymes serve as catalysts, increasing the rate of reaction without being consumed.

Question 2

Which of the following is an example of a catabolic pathway?

Accepted Answer

Breakdown of proteins into amino acids.

Question 3

What is the main difference between kinetic and potential energy in biological systems?

Accepted Answer

Kinetic energy is the energy of movement, while potential energy is stored energy due to position or structure.

Question 4

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

Accepted Answer

Energy can be transferred and transformed, but cannot be created or destroyed.

Question 5

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

Accepted Answer

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

Question 6

A reaction has $$\Delta G = +5$$ kcal/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is non-spontaneous and requires energy input to proceed.

Question 7

Why is ATP considered the primary energy currency of the cell?

Accepted Answer

ATP stores energy in its phosphate bonds, which can be hydrolyzed to release energy for cellular work.

Question 8

Which process is an example of energy coupling in cells?

Accepted Answer

Using the energy released from ATP hydrolysis to drive the synthesis of sucrose from glucose and fructose.

Question 9

What happens to a cell that reaches equilibrium in its metabolic reactions?

Accepted Answer

It stops performing work and is considered dead.

Question 10

Which of the following best describes the induced fit model of enzyme activity?

Accepted Answer

The enzyme changes shape slightly to better fit the substrate, enhancing catalysis.

Question 11

Which factor does NOT directly affect enzyme activity?

Accepted Answer

The color of the enzyme

Question 12

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Competing with the substrate for binding at the active site.

Question 13

Which statement about noncompetitive inhibition is correct?

Accepted Answer

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

Question 14

Which of the following is a real-world example of enzyme inhibition?

Accepted Answer

Penicillin inhibiting the enzyme that produces bacterial cell walls.

Question 15

Which statement about feedback inhibition in metabolic pathways is true?

Accepted Answer

The end product of a pathway inhibits an earlier step, usually by allosteric regulation.

Question 16

Which of the following best explains why heat is not a suitable way to overcome activation energy in cells?

Accepted Answer

Heat would denature proteins and speed up all reactions uncontrollably.

Question 17

Which of the following is NOT a macromolecule found in living organisms?

Accepted Answer

Glucose

Question 18

If the hydrolysis of ATP to ADP and $$P_i$$ releases $$7.5$$ kcal/mol of energy, what type of reaction is this?

Accepted Answer

Exergonic

Question 19

Which of the following statements about entropy is correct?

Accepted Answer

Every energy transfer increases the entropy of the universe.

Question 20

Which of the following is a cofactor required for enzyme activity?

Accepted Answer

Zinc ion

Introduction to Metabolism: Chemical Reactions, Energy, and Enzyme Function

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