Question 1

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

Accepted Answer

Hydrophilic heads face both the extracellular fluid and cytoplasm, while hydrophobic tails face each other.

Question 2

Which property of the plasma membrane allows oxygen and carbon dioxide to pass through easily, but restricts ions like $\mathrm{Na^+}$ and $\mathrm{Cl^-}$?

Accepted Answer

The selective permeability of the phospholipid bilayer

Question 3

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will burst (lyse) because water moves into the cell.

Question 4

Which of the following is a function of membrane carbohydrates such as glycolipids and glycoproteins?

Accepted Answer

Marking the cell for recognition as 'self' or 'non-self'

Question 5

Which process requires energy in the form of ATP to move substances across the plasma membrane against their concentration gradient?

Accepted Answer

Active transport

Question 6

The sodium-potassium pump ($\mathrm{Na^+/K^+}$ ATPase) is essential for nerve cell function. Which of the following best describes its action?

Accepted Answer

It moves $\mathrm{Na^+}$ out of the cell and $\mathrm{K^+}$ into the cell, both against their concentration gradients, using ATP.

Question 7

Which of the following best explains why ions such as $\mathrm{Cl^-}$ and $\mathrm{Na^+}$ require transport proteins to cross the plasma membrane?

Accepted Answer

They are hydrophilic and cannot pass through the hydrophobic core of the membrane.

Question 8

A cell is observed to engulf a bacterium by wrapping its membrane around it and forming a vesicle. Which process is being described?

Accepted Answer

Phagocytosis

Question 9

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It moves molecules from high to low concentration using channel or carrier proteins.

Question 10

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

Accepted Answer

It will become plasmolyzed as water leaves the cell.

Question 11

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

Accepted Answer

Phospholipids and proteins can move laterally within the layer, and proteins are scattered to form a mosaic pattern.

Question 12

Which type of membrane protein is NOT embedded in the lipid bilayer but is instead attached to the membrane surface?

Accepted Answer

Peripheral protein

Question 13

Which of the following is an example of active transport in cells?

Accepted Answer

Sodium-potassium pump moving $\mathrm{Na^+}$ out and $\mathrm{K^+}$ in

Question 14

Which process involves the fusion of vesicles with the plasma membrane to release their contents outside the cell?

Accepted Answer

Exocytosis

Question 15

A white blood cell engulfs a pathogen by forming a vesicle around it. Which type of endocytosis is this?

Accepted Answer

Phagocytosis

Question 16

Which of the following best explains why glucose requires a carrier protein to cross the plasma membrane?

Accepted Answer

Glucose is a large polar molecule and cannot diffuse through the hydrophobic core.

Question 17

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

Accepted Answer

Energy storage

Question 18

A cell uses receptor-mediated endocytosis to take in cholesterol from the bloodstream. What is the advantage of this process?

Accepted Answer

It enables the cell to selectively take in specific molecules bound to receptors.

Question 19

Which of the following scenarios best illustrates the concept of tonicity?

Accepted Answer

A plant cell in pure water becomes turgid due to water entering the cell.

Question 20

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the movement of water from low to high solute concentration across a selectively permeable membrane.

Membrane Structure and Function: Study Notes

Study Guide - Practice Questions

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