Question 1

Which of the following best describes the process of osmosis across a cell membrane?

Accepted Answer

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

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome, and why?

Accepted Answer

The cell will swell and may burst because water enters the cell due to osmosis.

Question 3

Which of the following is an example of active transport in cells?

Accepted Answer

The sodium-potassium pump moving $$\mathrm{Na^+}$$ out of and $$\mathrm{K^+}$$ into the cell using ATP.

Question 4

Which statement best explains why plant cells become turgid in a hypotonic solution?

Accepted Answer

Water enters the cell, filling the central vacuole and pressing the plasma membrane against the cell wall.

Question 5

Which of the following best describes exocytosis?

Accepted Answer

A vesicle fuses with the plasma membrane to release its contents outside the cell.

Question 6

A plant cell is placed in a hypertonic solution. What will happen to the cell?

Accepted Answer

The cell will lose water and become plasmolyzed as the plasma membrane pulls away from the cell wall.

Question 7

Which of the following statements about the laws of thermodynamics is correct?

Accepted Answer

The first law states that energy cannot be created or destroyed, only transformed.

Question 8

Which of the following reactions is exergonic?

Accepted Answer

The hydrolysis of ATP to ADP and $$\mathrm{P_i}$$, releasing energy.

Question 9

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy required for a reaction to proceed.

Question 10

A scientist observes that a certain enzyme only binds to its substrate after a slight change in the enzyme's shape. Which hypothesis does this observation support?

Accepted Answer

The induced fit hypothesis.

Question 11

Which of the following is an example of kinetic energy in a biological system?

Accepted Answer

The movement of ions through a channel protein.

Question 12

Which of the following scenarios best illustrates an endergonic reaction?

Accepted Answer

Photosynthesis, where light energy is used to build glucose from $$\mathrm{CO_2$}$$ and $$\mathrm{H_2O}.$$

Question 13

A patient is given an intravenous solution that is isotonic to their blood cells. What effect will this have on the cells?

Accepted Answer

There will be no net movement of water, and the cells will remain normal.

Question 14

Which of the following best explains why entropy ($$S) $$tends to increase in natural processes?

Accepted Answer

Energy transformations are never 100% efficient, so some energy is always lost as heat, increasing disorder.

Question 15

Which of the following is NOT a function of the plasma membrane?

Accepted Answer

Synthesizing ATP from ADP and $$\mathrm{P_i}.$$

Question 16

A cell uses endocytosis to take in large particles. Which of the following best describes this process?

Accepted Answer

The plasma membrane engulfs the particle, forming a vesicle that brings it into the cell.

Question 17

Which of the following statements about enzyme-substrate interactions is correct?

Accepted Answer

The substrate binds to the enzyme's active site, forming an enzyme-substrate complex.

Question 18

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

Accepted Answer

The energy stored in the chemical bonds of molecules such as glucose.

Question 19

A cell is placed in a solution and water moves out of the cell, causing it to shrink. Which type of solution is the cell in?

Accepted Answer

Hypertonic solution.

Question 20

Which of the following is true regarding the effect of enzymes on the activation energy ($$E_a) of a $$reaction?

Accepted Answer

Enzymes decrease $$E_a$$, allowing reactions to proceed faster at lower temperatures.

Chapter 5: The Working Cell – Membrane Transport, Energy, and Enzyme Function

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