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

$$\text{Water moves from an area of low solute concentration to an area of high solute concentration}$$

Question 1

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

Accepted Answer

A hydrophilic head and two hydrophobic tails

Question 2

The fluid mosaic model of the plasma membrane states that:

Accepted Answer

Phospholipids and proteins can move laterally within the layer, creating a dynamic structure

Question 3

Which of the following molecules will diffuse most quickly across a pure phospholipid bilayer?

Accepted Answer

O$$_2$$

Question 4

A winter wheat plant increases the percentage of unsaturated phospholipids in its cell membranes during autumn. What is the biological advantage of this adaptation?

Accepted Answer

It increases membrane fluidity to maintain function at lower temperatures

Question 5

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

Accepted Answer

Energy storage

Question 6

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

Accepted Answer

It will lose water and shrink

Question 7

Which equation best describes the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from an area of low solute concentration to an area of high solute concentration}$$

Question 8

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses membrane proteins to move molecules down their concentration gradient

Question 9

What is the role of cholesterol in animal cell membranes?

Accepted Answer

It acts as a fluidity buffer, stabilizing membrane fluidity at different temperatures

Question 10

Which of the following best explains why ions such as Na$$^{+}$$ cannot easily cross the phospholipid bilayer by simple diffusion?

Accepted Answer

They are hydrophilic and repelled by the hydrophobic core of the bilayer

Question 11

A marine algal cell is suddenly transferred from seawater to freshwater. What will happen to the cell initially?

Accepted Answer

It will absorb water and increase in volume

Question 12

Which process requires energy input from ATP to move substances across the membrane?

Accepted Answer

Active transport

Question 13

Which of the following is a real-life example of co-transport in humans?

Accepted Answer

Sodium-glucose transporter in intestinal cells absorbing nutrients

Question 14

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the movement of water to higher solute concentration

Question 15

Which type of membrane transport protein forms a hydrophilic pore that can be gated to open or close in response to signals?

Accepted Answer

Channel protein

Question 16

Which of the following best describes the process of exocytosis?

Accepted Answer

A vesicle fuses with the plasma membrane to release its contents outside the cell

Question 17

Which of the following membrane components is most important for cell-cell recognition?

Accepted Answer

Glycoproteins

Question 18

If a cell accumulates water from its environment, which membrane protein is most likely involved in speeding up this process?

Accepted Answer

Aquaporin

Question 19

Which of the following changes would make a cell membrane more fluid at room temperature?

Accepted Answer

Increasing the proportion of unsaturated fatty acids

Question 20

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

Accepted Answer

There will be no net movement of water

Cell Membranes: Structure and Function

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