Question

the diagram shown depicts a solute moving from
a. low concentration to high concentration by active transport
b. low concentration to high concentration by diffusion
c. high concentration to low concentration by active transport
d. high concentration to low concentration by diffusion

Explanation:

Step1: Analyze solute concentration

In the diagram, the cytoplasm (inside the cell) has fewer positive solute particles than the outside. So the solute is moving from low (cytoplasm) to high (outside) concentration? Wait, no—wait, the arrows: the solute (positive ions) are moving from cytoplasm (lower concentration, since fewer +) to outside (higher concentration, more +).

Step2: Identify transport type

Diffusion is from high to low. Active transport is from low to high (needs energy, often uses protein pumps or channels, but here the direction is against concentration gradient). So moving from low to high is active transport. Let's check options:

• Option A: low to high by active transport. Correct.
• Option B: low to high by diffusion (diffusion is high to low, so B wrong).
• Option C: high to low by active transport (active transport is low to high, so C wrong).
• Option D: high to low by diffusion (but diagram shows moving to higher concentration outside, so D wrong).

Answer:

A. low concentration to high concentration by active transport