Question 1

Which statement best describes the difference between kinetic energy and potential energy in biological systems?

Accepted Answer

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

Question 2

For an exergonic reaction, what is the sign of $$\Delta G$$ and what does it indicate about the reaction?

Accepted Answer

$$\Delta G is $$negative, indicating the reaction releases energy and is spontaneous.

Question 3

Cellular respiration is classified as which type of reaction, and what is the energy source that drives it?

Accepted Answer

Exergonic; driven by the breakdown of glucose.

Question 4

Which of the following best describes energy coupling in cells?

Accepted Answer

Energy coupling is the process of using energy from exergonic reactions to drive endergonic reactions.

Question 5

A biosynthetic reaction has a standard free-energy change $$\Delta G^\circ of$$ $$+5.5$$ kcal/mol. The hydrolysis of ATP to ADP has a $$\Delta G^\circ of$$ $$-7.3$$ kcal/mol. If these reactions are coupled, what is the overall $$\Delta G^\circ$$?

Accepted Answer

$$-1.8$$ kcal/mol

Question 6

What is the role of a catalyst in a chemical reaction?

Accepted Answer

A catalyst lowers the activation energy ($$E_a) $$and increases the reaction rate without being consumed.

Question 7

How does an enzyme affect the activation energy ($$E_a) $$and the free energy change ($$\Delta G) of a $$reaction?

Accepted Answer

It lowers $$E_a$$ but does not change $$\Delta G.$$

Question 8

Which statement best explains the induced fit model of enzyme activity?

Accepted Answer

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

Question 9

Why do extremes of pH or very high temperatures affect enzyme activity?

Accepted Answer

They denature the enzyme, altering its three-dimensional structure and active site.

Question 10

Which of the following best distinguishes competitive inhibitors from noncompetitive inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind elsewhere on the enzyme.

Question 11

Which process describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme involved early in the pathway.

Question 12

Why are living cells not at chemical equilibrium, and how do they avoid it?

Accepted Answer

Cells avoid equilibrium by maintaining a constant flow of materials and energy through open systems.

Question 13

Which statement correctly describes the difference between fermentation and aerobic respiration?

Accepted Answer

Fermentation produces less ATP per glucose molecule than aerobic respiration.

Question 14

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 15

What is the main function of the electron transport chain in cellular respiration?

Accepted Answer

To create a proton gradient across the inner mitochondrial membrane.

Question 16

Which stage of cellular respiration occurs in the cytoplasm?

Accepted Answer

Glycolysis

Question 17

In glycolysis, what is the net gain of ATP per glucose molecule, and what are the other high energy molecules produced?

Accepted Answer

Net gain of 2 ATP; NADH is also produced.

Question 18

Which of the following is NOT a product of glucose oxidation during cellular respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 19

How does ATP synthase use the proton gradient to produce ATP, and what is this process called?

Accepted Answer

ATP synthase uses the proton gradient to drive the synthesis of ATP from ADP and inorganic phosphate; this process is called chemiosmosis.

General Biology Study Guide: Energy, Metabolism, Enzymes, Cellular Respiration, and Fermentation

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