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 statements explains why phospholipids spontaneously form bilayers in water?

Accepted Answer

Hydrophilic heads interact with water, while hydrophobic tails avoid it.

Question 3

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

Accepted Answer

They serve as identification tags recognized by other cells.

Question 4

A scientist observes that ions cannot cross a plasma membrane efficiently without transport proteins. Which property of the membrane does this illustrate?

Accepted Answer

The membrane is selectively permeable.

Question 5

Which of the following best distinguishes between channel proteins and carrier proteins in the plasma membrane?

Accepted Answer

Channel proteins form open pores for molecules to pass through; carrier proteins bind to specific molecules and change shape to transport them.

Question 6

Which of the following processes does NOT require energy input from the cell?

Accepted Answer

Facilitated diffusion of glucose.

Question 7

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

Water will move into the cell, causing it to swell and possibly burst.

Question 8

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

Accepted Answer

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

Question 9

Which of the following best describes the process of osmosis?

Accepted Answer

The movement of water molecules from low to high solute concentration across a selectively permeable membrane.

Question 10

A cell uses ATP to pump sodium ions out and potassium ions in against their concentration gradients. Which type of transport is this?

Accepted Answer

Active transport

Question 11

Which of the following is true about cotransport in cell membranes?

Accepted Answer

It uses the energy from the movement of one substance down its gradient to transport 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 pinocytosis from receptor-mediated endocytosis?

Accepted Answer

Pinocytosis is non-specific uptake of fluids, while receptor-mediated endocytosis is specific for certain molecules.

Question 14

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

Accepted Answer

There will be no net movement of water into or out of the cell.

Question 15

Which of the following is an example of facilitated diffusion?

Accepted Answer

Glucose entering a cell through a carrier protein.

Question 16

Which of the following best explains why ions cannot easily cross the plasma membrane?

Accepted Answer

Ions are repelled by the hydrophobic interior of the lipid bilayer.

Question 17

Which of the following is true about the fluid mosaic model of the plasma membrane?

Accepted Answer

Proteins and lipids can move laterally within the layer.

Question 18

A cell is exposed to a hypertonic solution. Predict the direction of water movement and the effect on the cell.

Accepted Answer

Water will move out of the cell, causing it to shrink.

Question 19

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

Accepted Answer

They provide a pathway for molecules to move down their concentration gradient without using energy.

Membrane Structure and Function: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard