Q: Given the following values for a reaction: $$\Delta H = -40.0\ \text{kJ/mol}$$, $$\Delta S = -0.100\ \text{kJ/mol}\cdot\text{K}$$, and $$T = 350\ \text{K}$$, calculate $$\Delta G$$ using the Gibbs free energy equation.

$$\Delta G = -40.0 - (350 \times -0.100) = -40.0 + 35.0 = -5.0\ \text{kJ/mol}$$

Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules, while anabolic pathways consume energy to build complex molecules.

Question 2

A boulder at the top of a hill is an example of which type of energy?

Accepted Answer

Potential energy

Question 3

Which law of thermodynamics explains why energy is not lost but transformed into different forms, such as heat, during metabolic reactions?

Accepted Answer

The First Law of Thermodynamics

Question 4

Given the following values for a reaction: $$\Delta H = -40.0\ 	ext{kJ/mol}$$, $$\Delta S = -0.100\ 	ext{kJ/mol}\cdot	ext{K}$$, and $$T = 350\ 	ext{K}$$, calculate $$\Delta G$$ using the Gibbs free energy equation.

Accepted Answer

$$\Delta G = -40.0 - (350 	imes -0.100) = -40.0 + 35.0 = -5.0\ 	ext{kJ/mol}$$

Question 5

If a reaction has $$\Delta G = +8.0\ 	ext{kJ/mol}$$, which of the following statements is true?

Accepted Answer

The reaction is nonspontaneous and endergonic.

Question 6

Which of the following best explains why enzymes are necessary for exergonic reactions in cells?

Accepted Answer

Enzymes lower the activation energy ($$E_A$$), allowing reactions to proceed at a biologically useful rate.

Question 7

Refer to the first image. What does the vertical arrow labeled $$E_A$$ represent in the context of the reaction?

Accepted Answer

The activation energy required to reach the transition state.

Question 8

Which of the following is NOT a function of ATP in the cell?

Accepted Answer

Serving as a long-term energy storage molecule

Question 9

In the ATP cycle, which process is responsible for regenerating ATP from ADP?

Accepted Answer

Catabolic pathways provide the energy to phosphorylate ADP.

Question 10

Which of the following statements about enzyme specificity is correct?

Accepted Answer

The shape of the active site determines which substrate the enzyme can bind.

Question 11

Refer to the second image. Which type of enzyme inhibition is depicted in panel (b), and how can it be overcome?

Accepted Answer

Competitive inhibition; by increasing substrate concentration.

Question 12

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway acts as an allosteric inhibitor of an enzyme early in the pathway.

Question 13

Which of the following is an example of an inorganic cofactor required for enzyme function?

Accepted Answer

Iron

Question 14

A reaction has $$\Delta G = -12.0\ 	ext{kJ/mol}$$ and proceeds with a net release of free energy. Which term best describes this reaction?

Accepted Answer

Exergonic

Question 15

Which of the following environmental factors can denature an enzyme and reduce its activity?

Accepted Answer

Extreme pH

Question 16

Which of the following statements about allosteric regulation is true?

Accepted Answer

Allosteric inhibitors stabilize the inactive form of the enzyme.

Question 17

Which of the following best explains why living cells are considered open systems?

Accepted Answer

They exchange both energy and matter with their surroundings, preventing equilibrium.

Question 18

Which of the following is a real-life example of energy coupling in cells?

Accepted Answer

ATP hydrolysis powers the active transport of sodium and potassium ions across the cell membrane.

Question 19

Which of the following best describes the role of phosphorylation in cellular work?

Accepted Answer

It transfers a phosphate group from ATP to another molecule, making the recipient more reactive.

Question 20

Which of the following scenarios illustrates cooperativity in enzyme regulation?

Accepted Answer

A substrate binds to one active site, triggering a shape change that increases activity at other active sites.

Metabolism: Energy, Enzymes, and Regulation

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