Question

A student is experimenting with a substance that moves into the cell via facilitated diffusion.The student notes that as the concentration of the substance outside of the cell increases, the rate of movement of the substance into the cell increase and

then plateaus. What explains the phenomenon seen by the student?

Answer 1

Answer: A

Explanation: Facilitated diffusion requires transport proteins, which will become saturated at high levels of the substance. Facilitated diffusion does not require ATP energy nor does it require water. it does require helper proteins, which are not infinite. The proteins will become saturated at some point. This will make the rate of facilitated diffusion level out at some point.

Answer 2

Facilitated diffusion in a cell has a limited amount of carrier and channel proteins, wherein if all are being used or saturated, can't transport the substances outside in to the cell, leading to the plateau of the substance.

Step-by-step explanation:

In low concentrations of the substance outside the cell, facilitated diffusion behaves like simple diffusion, carriers and channels are not all used up. But in instances of high concentration of the substance outside the cell, all the carrier and channel proteins are occupied with the said substance. So even if we increase the concentration of the substance, it will not increase the rate of diffusion.