Question 1

Which of the following best describes the function of the cell membrane?

Accepted Answer

It is selectively permeable, allowing certain substances to pass while blocking others.

Question 2

The 'fluid mosaic model' of the cell membrane suggests that:

Accepted Answer

The membrane is composed of many different molecules that move around and change positions.

Question 3

Which organelle is responsible for synthesizing lipids for the cell membrane?

Accepted Answer

Smooth endoplasmic reticulum

Question 4

What is the main structural component of the plasma membrane?

Accepted Answer

Phospholipids

Question 5

A cell membrane is described as 'selectively permeable.' What does this mean in a physiological context?

Accepted Answer

It allows only certain substances to pass while restricting others.

Question 6

Which process is performed by the smooth endoplasmic reticulum and is essential for the cell membrane?

Accepted Answer

Lipid synthesis

Question 7

If a mutation prevents the smooth endoplasmic reticulum from functioning, which of the following would most likely be affected?

Accepted Answer

The cell's ability to synthesize lipids for the membrane

Question 8

Which of the following best explains why the cell membrane is described as a 'mosaic'?

Accepted Answer

It contains many different types of molecules, such as proteins, lipids, and carbohydrates.

Question 9

Which of the following is a real-life example of the importance of selective permeability in the cell membrane?

Accepted Answer

A red blood cell swelling and bursting in pure water due to uncontrolled water entry.

Question 10

Which of the following equations best represents the movement of water across a selectively permeable membrane?

Accepted Answer

$$ \Delta \Psi = \Psi_s + \Psi_p $$

Question 11

Which of the following statements about the fluid mosaic model is correct?

Accepted Answer

Proteins and lipids can move laterally within the layer, giving the membrane flexibility.

Question 12

Which of the following best describes the role of phospholipids in the plasma membrane?

Accepted Answer

They create a flexible bilayer that allows selective movement of substances.

Question 13

A scientist observes that a cell is unable to maintain homeostasis. Which malfunction in the cell membrane could most likely cause this?

Accepted Answer

The membrane becomes completely permeable to all substances.

Question 14

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

Accepted Answer

Synthesizes DNA for the cell

Question 15

Which of the following best explains why the cell membrane is described as 'fluid'?

Accepted Answer

The molecules within the membrane can move laterally, allowing flexibility.

Question 16

Which of the following would most likely happen if the phospholipids in the plasma membrane were replaced with triglycerides?

Accepted Answer

The membrane would lose its selective permeability and become nonfunctional.

Question 17

Which of the following is a direct consequence of the cell membrane's selective permeability in a medical context?

Accepted Answer

Certain drugs can enter cells while others cannot, affecting treatment effectiveness.

Question 18

Which of the following best describes the process of 'desaturation' as it relates to the cell membrane?

Accepted Answer

The process of introducing double bonds into fatty acid chains, increasing membrane fluidity.

Question 19

Which of the following best explains how the cell membrane helps maintain homeostasis?

Accepted Answer

By selectively allowing certain substances to enter or leave the cell, maintaining internal balance.

Question 20

Which of the following is a correct statement about the relationship between the smooth endoplasmic reticulum and the plasma membrane?

Accepted Answer

The smooth endoplasmic reticulum synthesizes phospholipids that are incorporated into the plasma membrane.

Cell Membrane Structure and Function

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