Question 1

Which of the following best describes the amphipathic nature of phospholipids in the plasma membrane?

Accepted Answer

They have both a hydrophilic head and a hydrophobic tail.

Question 2

Which component of the plasma membrane acts as a 'fluidity buffer,' preventing the membrane from becoming too rigid or too fluid?

Accepted Answer

Cholesterol

Question 3

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

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 4

Which of the following molecules can most easily diffuse through the phospholipid bilayer without the help of a transport protein?

Accepted Answer

O$$_2$$

Question 5

Which of the following statements about membrane proteins is correct?

Accepted Answer

Integral proteins penetrate the hydrophobic core of the lipid bilayer.

Question 6

Which process requires energy input in the form of ATP to move substances across the plasma membrane?

Accepted Answer

Active transport

Question 7

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

Accepted Answer

The cell becomes turgid due to water entering the cell.

Question 8

Which of the following best explains why unsaturated fatty acids increase membrane fluidity?

Accepted Answer

Their kinks prevent tight packing of phospholipids.

Question 9

Which type of membrane protein is primarily responsible for cell-to-cell recognition?

Accepted Answer

Glycoproteins

Question 10

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

Accepted Answer

Cotransport of glucose with Na$$^+$$

Question 11

According to Fick’s law, which of the following changes would increase the rate of diffusion across a membrane?

Accepted Answer

Increasing the surface area

Question 12

Which of the following best describes the function of aquaporins?

Accepted Answer

They facilitate the transport of water across the membrane.

Question 13

Which of the following scenarios best illustrates the concept of selective permeability?

Accepted Answer

O$$_2$$ diffuses rapidly while Na$$^+$$ requires a channel protein.

Question 14

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

Accepted Answer

Synthesis of DNA

Question 15

A white blood cell engulfs a bacterium by surrounding it with its plasma membrane. This process is best described as:

Accepted Answer

Phagocytosis

Question 16

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires a transport protein but does not require energy.

Question 17

Which of the following would most likely decrease the permeability of a cell membrane to water?

Accepted Answer

Removing aquaporins

Question 18

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

Accepted Answer

Plant cells have a rigid cell wall that prevents bursting.

Question 19

Which of the following is a real-life example of exocytosis?

Accepted Answer

Secretion of mucus by goblet cells

Question 20

Which of the following best describes the role of glycolipids and glycoproteins in the plasma membrane?

Accepted Answer

They are involved in cell-to-cell recognition.

Membrane Structure and Function: The Fluid Mosaic Model and Membrane Transport

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