Question 1

Which of the following best describes the structure of a phospholipid in a biological membrane?

Accepted Answer

A molecule with a hydrophilic head and two hydrophobic tails.

Question 2

Which of the following is a function of membrane carbohydrates in cell-cell recognition?

Accepted Answer

They serve as identification tags that are recognized by other cells.

Question 3

A scientist observes that ions cannot cross a plasma membrane efficiently without assistance. Which membrane component is most likely responsible for facilitating their movement?

Accepted Answer

Channel proteins

Question 4

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

Accepted Answer

The hydrophilic heads interact with water, while the hydrophobic tails avoid water.

Question 5

Which of the following statements about passive transport is correct?

Accepted Answer

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

Question 6

A red blood cell is placed in a solution with a lower solute concentration than its cytoplasm. What will happen to the cell?

Accepted Answer

It will swell and possibly burst as water enters the cell.

Question 7

Which equation correctly represents the calculation of water potential ($\Psi$) in plant cells?

Accepted Answer

$\Psi = \Psi_s + \Psi_p$

Question 8

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion uses membrane proteins to transport substances across the membrane.

Question 9

Which of the following best describes the role of carrier proteins in membrane transport?

Accepted Answer

They bind specific molecules and change shape to shuttle them across the membrane.

Question 10

A cell uses energy to pump sodium ions out and potassium ions in, maintaining a concentration gradient. This process is an example of:

Accepted Answer

Active transport

Question 11

Which of the following is true about cotransport?

Accepted Answer

It uses the energy from the movement of one substance down its gradient to move another substance against its gradient.

Question 12

Which process is responsible for the uptake of large molecules, such as proteins, into a cell?

Accepted Answer

Endocytosis

Question 13

Which of the following best distinguishes between pinocytosis and receptor-mediated endocytosis?

Accepted Answer

Receptor-mediated endocytosis is specific for certain molecules, while pinocytosis is non-specific.

Question 14

A cell is placed in an isotonic solution. What will happen to the net movement of water across its membrane?

Accepted Answer

There will be no net movement of water.

Question 15

Which of the following best describes the difference between peripheral and integral membrane proteins?

Accepted Answer

Integral proteins are embedded within the lipid bilayer, while peripheral proteins are loosely attached to the surface.

Question 16

Which of the following scenarios best illustrates osmosis?

Accepted Answer

Water moving from an area of low solute concentration to high solute concentration across a semipermeable membrane.

Question 17

Which of the following is NOT a factor that affects the rate of diffusion across a membrane?

Accepted Answer

The color of the molecule

Question 18

A patient is given intravenous fluids that are hypotonic compared to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

The cells will swell and may burst due to water influx.

Question 19

Which of the following best describes the process of facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient with the help of membrane proteins.

Question 20

Which of the following is a real-world example of active transport in human physiology?

Accepted Answer

Sodium-potassium pump maintaining ion gradients in nerve cells.

Membrane Structure and Function: Study Notes

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