Question

the video shows that carbon dioxide molecules have a net movement from an area of higher concentration to an area of lower concentration, until they have an equal concentration on either side of the cell membrane. in other words, there is no net movement once carbon dioxide molecules reach a state of equilibrium. select the true statements. molecules diffuse across a cell membrane until they are all outside the cell. once equilibrium is reached, molecules continue to cross the cell membrane. molecules move up their concentration gradient to reach equilibrium. equilibrium is reached when molecules have an equal concentration on both sides of the cell membrane.

Explanation:

• For B, at equilibrium, there is no net - movement but molecules still cross in both directions.
• For D, by definition of equilibrium in diffusion across a membrane, concentrations on both sides become equal.

Answer:

B. Once equilibrium is reached, molecules continue to cross the cell membrane.
D. Equilibrium is reached when molecules have an equal concentration on both sides of the cell membrane.