Question

molecules will move through a selectively permeable membrane until there is a balanced concentration on both sides of the membrane. which of the following statements best describes the cell transport shown in the picture above? a) passive transport because particles are moving with their concentration gradient until they are evenly dispersed. b) active transport because particles are moving against their concentration gradient until they are evenly dispersed. c) active transport because particles are moving with their concentration gradient until they are evenly dispersed. d) passive transport because particles are moving against their concentration gradient until they are evenly dispersed.

Explanation:

To determine the correct answer, we analyze the concepts of passive and active transport:

1. Passive Transport: Molecules move from an area of higher concentration to an area of lower concentration (with the concentration gradient) and does not require energy. Examples include diffusion and osmosis. The goal is to reach equilibrium (even dispersion).
2. Active Transport: Molecules move from an area of lower concentration to an area of higher concentration (against the concentration gradient) and requires energy (e.g., ATP).

In the diagram, particles are moving until they are evenly dispersed, which indicates movement with the concentration gradient (from high to low concentration) until equilibrium is reached. This matches passive transport.

Now let's analyze the options:

• Option A: States "Passive transport because particles are moving with their concentration gradient until they are evenly dispersed." This aligns with the definition of passive transport (movement with the gradient to reach equilibrium).
• Option B: Claims "Active transport because particles are moving against their concentration gradient until they are evenly dispersed." Active transport is against the gradient, but the goal of passive transport (not active) is even dispersion via moving with the gradient. So this is incorrect.
• Option C: States "Active transport because particles are moving with their concentration gradient until they are evenly dispersed." Active transport does not move with the gradient; it moves against it. So this is incorrect.
• Option D: Claims "Passive transport because particles are moving against their concentration gradient until they are evenly dispersed." Passive transport moves with the gradient, not against. So this is incorrect.

Answer:

A. Passive transport because particles are moving with their concentration gradient until they are evenly dispersed.