The transportation of substances in and out of a cell is regulated by the cell membrane.

Question

Describe two factors that increase the rate of diffusion of a molecule across the cell membrane.

Answer 1

The cell membrane is the outer covering of the cell and acts as a sort of gate around the cell to protect its contents, keep the desirable stuff inside of the cell, and keep things it doesn’t need outside the cell. The cell membrane does allow some stuff to enter and exit the cell, which is important for regulating water content, transporting proteins, and more... when water moves across the cell membrane, it’s called osmosis. When another molecule other than water moves across the cell membrane, it is called diffusion. There are actually more than 2 things that can affect the rate of diffusion, but these are the two big ones to know...

1. Temperature- higher temperature means molecules move around faster! With all of these molecules zipping around, they bump into the cell more quickly and therefore increase the rate that they’re transported across the cell membrane.
2. Concentration Gradient- the bigger the difference in the amount of molecules inside versus the outside of the cell, the faster the molecules want to travel to the side with the smaller concentration to achieve equilibrium (equal balance of molecules on either side of cell membrane)