Question 1

Which of the following best describes potential energy in a biological context?

Accepted Answer

Energy stored in chemical bonds and gradients, available to do work

Question 2

A ball is placed at the top of a hill and then allowed to roll down. Which type of energy transformation occurs as the ball moves?

Accepted Answer

Potential energy is converted to kinetic energy

Question 3

Which of the following statements about chemical bonds and potential energy is correct?

Accepted Answer

Long, weak bonds have more potential energy than short, strong bonds

Question 4

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

Accepted Answer

Energy can be transformed from one form to another, 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 a negative $$\Delta G. $$What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and can occur spontaneously

Question 7

Which of the following best describes entropy ($$S) in $$biological systems?

Accepted Answer

A measure of disorder or randomness in a system

Question 8

Why do spontaneous reactions not always occur rapidly in biological systems?

Accepted Answer

They may have a high activation energy ($$E_a) $$barrier

Question 9

Which of the following is an example of energetic coupling in cells?

Accepted Answer

Using the energy from ATP hydrolysis to drive an endergonic reaction

Question 10

In a redox (reduction-oxidation) reaction, what happens to the electron donor?

Accepted Answer

It loses electrons and is oxidized

Question 11

Which of the following factors will increase the rate of a chemical reaction in a cell?

Accepted Answer

Increasing the concentration of reactants

Question 12

What is the primary function of enzymes in biological reactions?

Accepted Answer

To lower the activation energy ($$E_a) $$required for a reaction

Question 13

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

Accepted Answer

A molecule resembling the substrate binds to the active site, blocking substrate binding

Question 14

Allosteric regulation of an enzyme involves:

Accepted Answer

A regulatory molecule binding to a different site, causing a conformational change

Question 15

Which of the following statements about metabolic pathways is correct?

Accepted Answer

They are often regulated by feedback inhibition from the pathway's end product

Question 16

A scientist increases the temperature of a solution containing an enzyme and its substrate. What is the most likely effect on the reaction rate?

Accepted Answer

The reaction rate will increase up to an optimal temperature, then decrease if the enzyme denatures

Question 17

Which of the following best explains why ATP is often used to drive endergonic reactions in cells?

Accepted Answer

Hydrolysis of ATP releases energy that can be coupled to endergonic reactions

Question 18

A patient is given a drug that acts as a noncompetitive inhibitor of a key metabolic enzyme. Which of the following is most likely to occur?

Accepted Answer

The drug binds to a different site, changing the enzyme's shape and reducing its activity

Question 19

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

Accepted Answer

The final product of a pathway inhibits an early enzyme in the pathway

Question 20

Which of the following statements about enzyme activity is correct?

Accepted Answer

Each enzyme has an optimal temperature and pH range for activity

Energy, Thermodynamics, and Enzyme Function in Biology

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