$$ \mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy} $$

Question 1

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

Accepted Answer

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

Question 2

A cyclist at the top of a hill has which type of energy, and what happens to it as they ride down?

Accepted Answer

Potential energy, which is converted to kinetic energy.

Question 3

Which of the following best explains why enzymes are necessary for life?

Accepted Answer

They lower the activation energy barrier, allowing reactions to occur at cellular temperatures.

Question 4

Which of the following is an example of an exergonic reaction?

Accepted Answer

Cellular respiration in animals

Question 5

What is the role of ATP in energy coupling within cells?

Accepted Answer

ATP couples exergonic and endergonic reactions by transferring a phosphate group.

Question 6

Which equation correctly represents the hydrolysis of ATP?

Accepted Answer

$$ \mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy} $$

Question 7

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

Accepted Answer

Enzyme activity is highest at an optimal temperature and decreases if the temperature is too high or too low.

Question 8

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site and blocking substrate binding.

Question 9

Which of the following is a coenzyme?

Accepted Answer

Vitamin B12

Question 10

Why are energy barriers (activation energy) necessary in biological reactions?

Accepted Answer

They prevent all reactions from occurring at once, allowing regulation.

Question 11

Which of the following best describes the effect of heavy metals on enzyme activity?

Accepted Answer

Heavy metals bind to sulfhydryl groups, changing enzyme structure and inhibiting activity.

Question 12

Which of the following statements about enzyme denaturation is correct?

Accepted Answer

Denaturation destroys the enzyme's 3-D structure, making it nonfunctional.

Question 13

Which of the following is true about noncompetitive enzyme inhibitors?

Accepted Answer

They bind to an allosteric site, changing the enzyme's shape and reducing activity.

Question 14

Which of the following best explains why pesticides can be harmful to humans?

Accepted Answer

They irreversibly inhibit enzymes involved in nerve impulse transmission.

Question 15

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

Accepted Answer

Using the energy from ATP hydrolysis to drive the synthesis of glucose from CO$$_2$$ and H$$_2O.$$

Question 16

Which of the following best describes the relationship between entropy and the Second Law of Thermodynamics?

Accepted Answer

Every energy transfer increases the entropy (disorder) of the universe.

Question 17

Which of the following scenarios best illustrates an endergonic reaction?

Accepted Answer

The synthesis of glucose during photosynthesis.

Question 18

Which of the following is true about the specificity of enzymes?

Accepted Answer

Enzyme specificity is determined by the enzyme's 3-D protein shape.

Question 19

Which of the following best describes the process of phosphorylation?

Accepted Answer

The addition of a phosphate group to a protein or enzyme, often regulating its activity.

Question 20

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

Accepted Answer

Penicillin inhibiting bacterial cell wall synthesis enzymes.

Enzymes and Cellular Energy: Thermodynamics, Function, and Regulation

Study Guide - Practice Questions