Question 1

Which of the following best describes the difference between potential energy and kinetic energy in a biological system?

Accepted Answer

Potential energy is stored energy, such as in chemical bonds or ion gradients, while kinetic energy is the energy of motion, such as the movement of molecules or ions.

Question 2

A cell stores potential energy in several ways. Which of the following is NOT a form of potential energy storage in cells?

Accepted Answer

The movement of water molecules across a membrane.

Question 3

Which of the following reactions is most likely to occur spontaneously in a cell?

Accepted Answer

A reaction where the reactants have a higher free energy than the products ($$\Delta G \u003c 0).$$

Question 4

Which statement best summarizes the first law of thermodynamics as it applies to cellular processes?

Accepted Answer

Energy cannot be created or destroyed, only transformed from one form to another.

Question 5

A plant cell is placed in a hypertonic solution. What is the most likely outcome?

Accepted Answer

The cell will lose water, and the plasma membrane will pull away from the cell wall (plasmolysis).

Question 6

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient through a membrane protein, without energy input.

Question 7

The sodium/potassium pump is an example of which type of membrane transport?

Accepted Answer

Primary active transport, because it uses ATP to move ions against their gradients.

Question 8

Which of the following best explains why animal cells must maintain an isotonic environment?

Accepted Answer

To prevent excessive water movement that could cause the cell to burst or shrink.

Question 9

Which of the following is a correct statement about entropy ($$S) in $$biological systems?

Accepted Answer

Entropy tends to increase in isolated systems, and cells must expend energy to maintain order.

Question 10

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP provides energy for endergonic reactions by transferring a phosphate group.

Question 11

A reaction has a positive $$\Delta G. $$Which of the following is true?

Accepted Answer

The reaction is endergonic and requires an input of energy to proceed.

Question 12

Which of the following is an example of secondary active transport?

Accepted Answer

Using the sodium gradient established by the sodium/potassium pump to drive glucose uptake into the cell.

Question 13

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

Accepted Answer

A molecule similar to the substrate binds to the active site, preventing substrate binding.

Question 14

Which of the following would most likely occur if a freshwater plant cell is placed in a hypotonic solution?

Accepted Answer

The cell will become turgid as water enters, but will not burst due to the cell wall.

Question 15

Which of the following is true about the energy of activation ($$E_A) in $$enzyme-catalyzed reactions?

Accepted Answer

Enzymes lower the energy of activation, allowing reactions to proceed more rapidly.

Question 16

Which of the following best describes osmosis?

Accepted Answer

The passive movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Question 17

Which of the following is an example of an anabolic pathway?

Accepted Answer

Synthesis of proteins from amino acids.

Question 18

A cell is placed in a solution and water moves into the cell, causing it to swell. Which term best describes the solution?

Accepted Answer

Hypotonic

Question 19

Which of the following best explains why cells use metabolic pathways rather than single-step reactions?

Accepted Answer

Metabolic pathways allow for regulation and energy capture at multiple steps.

Question 20

Which of the following is true about feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an earlier enzyme, preventing overproduction.

Biological Thermodynamics and Cross-Membrane Transport: Study Guide

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