Q: Which equation best describes the movement of water during osmosis?

$$\text{Water moves from an area of lower solute concentration to higher solute concentration}$$

Question 1

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

Accepted Answer

A molecule with a hydrophilic head and two hydrophobic tails

Question 2

According to the fluid mosaic model, which statement is correct about the plasma membrane?

Accepted Answer

Phospholipids and proteins can move laterally within the layer

Question 3

Which of the following changes would most likely increase the fluidity of a cell membrane at low temperatures?

Accepted Answer

Increasing the proportion of unsaturated fatty acids

Question 4

Cholesterol acts as a 'fluidity buffer' in animal cell membranes. What is its effect at high temperatures?

Accepted Answer

It decreases membrane fluidity by restraining phospholipid movement

Question 5

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

Accepted Answer

Synthesis of DNA

Question 6

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

Accepted Answer

It will gain water and burst (lyse)

Question 7

Which type of molecule can most easily cross the lipid bilayer of a plasma membrane without the aid of a protein?

Accepted Answer

Hydrophobic (nonpolar) molecules

Question 8

Facilitated diffusion differs from simple diffusion in that facilitated diffusion:

Accepted Answer

Requires transport proteins to move substances down their concentration gradient

Question 9

The sodium-potassium pump is an example of which type of membrane transport?

Accepted Answer

Active transport

Question 10

Which equation best describes the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from an area of lower solute concentration to higher solute concentration}$$

Question 11

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

Accepted Answer

The cell will plasmolyze

Question 12

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

Accepted Answer

Ions are hydrophilic and cannot pass through the hydrophobic core of the membrane

Question 13

Which process requires energy input from the cell?

Accepted Answer

Active transport

Question 14

Which of the following is a real-life example of receptor-mediated endocytosis?

Accepted Answer

Uptake of cholesterol by animal cells using LDL receptors

Question 15

A cell is placed in a solution and water moves into the cell. Which equation describes the tonicity of the solution relative to the cell?

Accepted Answer

$$	ext{[Solute]_{solution} \u003c [Solute]_{cell}}$$

Question 16

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

Accepted Answer

They allow water to diffuse rapidly across the membrane

Question 17

Which of the following is true about the sodium-potassium pump?

Accepted Answer

It moves 3 Na$$^+$$ ions out and 2 K$$^+$$ ions in per ATP hydrolyzed

Question 18

Which of the following best describes the electrochemical gradient?

Accepted Answer

It is the combined effect of the ion's concentration gradient and the membrane potential

Question 19

Which process is used by white blood cells to engulf bacteria?

Accepted Answer

Phagocytosis

Question 20

A scientist observes that a certain molecule can cross the plasma membrane only when a specific protein is present, and the process does not require ATP. Which type of transport is most likely occurring?

Accepted Answer

Facilitated diffusion

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