Question 1

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A double layer of phospholipids with proteins embedded, allowing lateral movement

Question 2

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

Accepted Answer

The cell will burst (lyse) due to water entering

Question 3

Which of the following molecules can most easily cross a pure phospholipid bilayer without the help of membrane proteins?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 4

What is the main function of ATP in cellular processes?

Accepted Answer

To provide energy for cellular work by transferring a phosphate group

Question 5

Which process requires energy input from the cell?

Accepted Answer

Active transport

Question 6

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

Accepted Answer

It will undergo plasmolysis and shrink away from the cell wall

Question 7

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrates

Question 8

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

Accepted Answer

A product of the pathway binds to an enzyme early in the pathway and decreases its activity

Question 9

Which statement about passive transport is correct?

Accepted Answer

It relies on the random movement of molecules and does not require energy

Question 10

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

Accepted Answer

The cell engulfs particles by wrapping the plasma membrane around them and forming a vesicle

Question 11

Which of the following best describes the role of membrane proteins in facilitated diffusion?

Accepted Answer

They provide a pathway for specific molecules to move down their concentration gradient

Question 12

Which law of thermodynamics explains why no energy transformation is 100% efficient and some energy is lost as heat?

Accepted Answer

Second law: Every energy transfer increases the entropy of the universe

Question 13

A cell is placed in an isotonic solution. What will happen to the cell?

Accepted Answer

It will remain the same size as water moves in and out at equal rates

Question 14

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

Accepted Answer

Hydrolysis of ATP to ADP and phosphate

Question 15

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophobic tails avoid water while hydrophilic heads interact with water

Question 16

A competitive inhibitor of an enzyme works by:

Accepted Answer

Binding to the active site and preventing substrate binding

Question 17

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

Accepted Answer

Storing genetic information

Question 18

If a cell needs to move glucose into the cytoplasm against its concentration gradient, which process will it use?

Accepted Answer

Active transport

Question 19

Which of the following best describes the process of osmosis?

Accepted Answer

Movement of water molecules across a selectively permeable membrane from low to high solute concentration

Question 20

A scientist adds a drug that blocks ATP production in a cell. Which of the following processes would be most directly affected?

Accepted Answer

Active transport of sodium ions

The Working Cell: Membrane Structure, Function, and Cellular Energy

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