Grade 9 Biology: Transport Mechanisms

Which of the following statements best explains the difference between diffusion and osmosis?

• Diffusion only occurs in gases, whereas osmosis only occurs in solids.

• Diffusion moves particles down a concentration gradient, while osmosis involves the movement of water across a semi-permeable membrane.

• Diffusion requires energy, while osmosis does not.

• Osmosis moves solutes against a concentration gradient, while diffusion does not.

A cell is placed in a solution, and it shrinks in size. Which of the following is most likely the explanation?

• The solution has a higher water concentration than the cell's cytoplasm.

• Active transport has caused water to leave the cell.

• The solution is hypertonic to the cell, causing water to move out via osmosis.

• Diffusion of solutes into the cell caused water to leave.

Which of the following scenarios illustrates active transport?

• Movement of oxygen into red blood cells.

• Uptake of glucose in the small intestine using protein pumps.

• Movement of urea out of cells via diffusion.

• Absorption of water by root hair cells in plants.

Diffusion is faster at higher temperatures because particles have more kinetic energy.

Osmosis can occur in both directions across a membrane, depending on the concentration gradient of water.

Active transport does not require a semi-permeable membrane.

If a plant cell is placed in a hypotonic solution, it becomes plasmolyzed.

In active transport, particles move from an area of low concentration to high concentration, requiring ATP.

Osmosis can occur even when the solute concentration on both sides of a membrane is equal if the membrane is impermeable to solutes.

Diffusion can occur against a concentration gradient if the particles are very small.