Question

What factors affect the rate of diffusion?

Answer 1

Diffusion:

1. Diffusion is defined as the movement of substances from an area of higher concentration to an area of lower concentration.
2. It is caused by a random movement.

Factors affecting the rate of diffusion

Concentration Gradient:

1. The rate of diffusion is proportional to the concentration difference across the cell membrane.
2. Hence, when the gradient is zero, there will be no diffusion.
3. Diffusion only will occur as long as a concentration gradient exists.
4. Example: $N{a}^{+}$ concentrations inside and outside cells.

Temperature:

1. As the rate of diffusion is directly proportional to the temperature of a substance.
2. If the temperature increases, so do the rate of diffusion.

Molecular weight:

1. As the rate of diffusion is inversely proportional to the molecular weight of a substance.
2. Heavier the molecules move more slowly than smaller, lighter ones.

Surface Area:

1. The greater the surface area is the greater the rate of diffusion.
2. More space area for absorption per given size of a cell.