Q: A reaction has $$\Delta H = -100 kJ/$$mol, $$\Delta S = 0.2 kJ/($$mol\cdot K),$$ and occurs at T = 300$ K. What is the value of $$\Delta G$ for this reaction?

$$\Delta G = -100 - (300 \times 0.2) = -160 kJ/$$mol

Question 1

Which of the following equations correctly represents the relationship between total internal energy (H), Gibbs free energy (G), temperature (T), and entropy (S) in a biological system?

Accepted Answer

$$H = G + TS$$

Question 2

A reaction has $$\Delta H = -100 kJ/$$mol, $$\Delta S = 0.2 kJ/($$mol\cdot K),$$ and occurs at T = 300$ K. What is the value of $$\Delta G$ for this reaction?

Accepted Answer

$$\Delta G = -100 - (300 	imes 0.2) = -160 kJ/$$mol

Question 3

Which statement best describes a spontaneous reaction in terms of Gibbs free energy?

Accepted Answer

A spontaneous reaction has $$\Delta G \u003c 0$$

Question 4

If a biological process requires an input of energy and results in a decrease in entropy, which of the following is true?

Accepted Answer

$$\Delta G \u003e 0$$ and $$\Delta S \u003c 0$$

Question 5

Which of the following best explains how life can persist despite the nonspontaneous nature of building complex molecules from simpler ones?

Accepted Answer

Cells use energy (such as ATP) to drive nonspontaneous reactions

Question 6

Which of the following is a correct interpretation of the equation $$\Delta G = \Delta H - T \Delta S$$?

Accepted Answer

The change in free energy equals the change in enthalpy minus the temperature times the change in entropy

Question 7

Which of the following is NOT a function of enzymes in biological systems?

Accepted Answer

Enzymes are consumed during the reaction

Question 8

What is the role of the active site in an enzyme-catalyzed reaction?

Accepted Answer

It binds substrates and lowers the activation energy

Question 9

Which of the following best describes competitive inhibition of an enzyme?

Accepted Answer

An inhibitor binds to the active site, blocking substrate binding

Question 10

A noncompetitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to a site other than the active site, causing a conformational change

Question 11

Which of the following scenarios would most likely result in a decrease in basal attentional performance according to recent scientific studies?

Accepted Answer

The mere presence of a smartphone in the environment

Question 12

Which of the following is a real-world example of enzyme regulation in medicine?

Accepted Answer

Antibiotics acting as enzyme inhibitors to block bacterial metabolism

Question 13

Which of the following statements about metabolic pathways is correct?

Accepted Answer

Cells can regulate metabolism by switching enzymes on or off

Question 14

Which of the following is true about the energy required to actively transport molecules across a membrane?

Accepted Answer

ATP provides the energy needed for active transport

Question 15

Which of the following best describes the difference between total internal energy and free energy in a system at constant temperature?

Accepted Answer

Free energy is the portion of total internal energy that can do work

Question 16

Which of the following is a correct multi-step application of the free energy equation for a reaction where $$\Delta H = 50 kJ/$$mol, $$\Delta S = 0.1 kJ/($$mol\cdot K),$$ and T = 298$ K?

Accepted Answer

$$\Delta G = 50 - (298 	imes 0.1) = 20.2 kJ/$$mol

Question 17

Which of the following is a consequence of the second law of thermodynamics for living organisms?

Accepted Answer

Organisms must use energy to maintain order and decrease entropy locally

Question 18

Which of the following is true about the hydrolysis of sucrose in the presence of the enzyme sucrase?

Accepted Answer

The reaction occurs much faster due to the enzyme lowering the activation energy

Question 19

Which of the following is an example of allosteric regulation of an enzyme?

Accepted Answer

An inhibitor binds to a site other than the active site, changing the enzyme's shape

Free Energy, Enzymes, and Metabolic Regulation in Biology

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