Question 1

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

Accepted Answer

A dynamic structure where phospholipids, proteins, and other molecules can move laterally, with various components embedded throughout.

Question 2

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

Accepted Answer

Synthesis of DNA within the nucleus

Question 3

A red blood cell is placed in a solution and begins to swell and eventually bursts. Which type of solution was the cell placed in?

Accepted Answer

Hypotonic solution

Question 4

Which of the following substances can diffuse directly across the plasma membrane without the help of membrane proteins?

Accepted Answer

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

Question 5

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion requires the assistance of membrane proteins.

Question 6

Which statement correctly compares channel proteins and carrier proteins?

Accepted Answer

Channel proteins form pores for specific ions, while carrier proteins bind and change shape to move substances.

Question 7

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

Accepted Answer

The cell becomes plasmolyzed as water leaves.

Question 8

Which of the following best describes active transport?

Accepted Answer

Movement of solutes against their concentration gradient using ATP.

Question 9

In neurons, the sodium-potassium pump is an example of:

Accepted Answer

Active transport

Question 10

Which of the following scenarios illustrates coupled transport (symport or antiport)?

Accepted Answer

A glucose molecule is transported into the cell while a sodium ion is transported out.

Question 11

Bulk transport is essential for which of the following cellular processes?

Accepted Answer

Moving large quantities of materials, such as during endocytosis or exocytosis

Question 12

Which of the following best explains why plant cells do not burst in a hypotonic solution?

Accepted Answer

The cell wall provides structural support and resists excessive expansion.

Question 13

A solution with a higher solute concentration than the cytoplasm of a cell is described as:

Accepted Answer

Hypertonic

Question 14

Which of the following is a real-life example of passive transport?

Accepted Answer

Oxygen entering red blood cells in the lungs

Question 15

Which process is responsible for the uptake of large particles, such as bacteria, by white blood cells?

Accepted Answer

Bulk transport (phagocytosis)

Question 16

Which of the following best describes the normal osmotic condition for animal cells?

Accepted Answer

Isotonic

Question 17

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the movement of water across a selectively permeable membrane.

Question 18

Which of the following best explains why turgor pressure is important for plant cells?

Accepted Answer

It helps maintain the shape and rigidity of the plant cell.

Question 19

Which of the following is true regarding the movement of solutes in active transport?

Accepted Answer

Solutes move against their concentration gradient, requiring energy.

Question 20

A scientist observes that a certain protein is embedded in the plasma membrane and is involved in signal transduction. Which of the following best describes the function of this protein?

Accepted Answer

It transmits information from the external environment to the cell's interior.

Membranes: Structure, Function, and Transport Mechanisms – Guided Study

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