Question

this video shows carbon dioxide crossing the cell membrane by simple diffusion. complete the paragraph. at the start of the video, there is a higher concentration of carbon dioxide molecules inside the cell than outside the cell. as carbon dioxide molecules move by simple diffusion, molecules cross the cell membrane in both directions. molecules move from inside the cell to the outside, until the concentration outside the cell is the concentration inside the cell. overall, the video shows that the net movement of carbon dioxide is its concentration gradient.

Explanation:

Simple diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. In this case, carbon dioxide moves down its concentration gradient. When molecules cross the membrane in both directions, equilibrium is reached when concentrations are equal. The net movement is always down the concentration gradient.

Answer:

At the start of the video, there is a higher concentration of carbon dioxide molecules inside the cell than outside the cell. As carbon dioxide molecules move by simple diffusion, molecules cross the cell membrane in both directions. More molecules move from inside the cell to the outside, until the concentration outside the cell is equal to the concentration inside the cell. Overall, the video shows that the net movement of carbon dioxide is down its concentration gradient.