Question

How does simple diffusion occur?

Answer 1

Diffusion:

1. A substance tends to move from a region of high concentration in diffusion to a region of lower concentration until equilibrium is reached.
2. The total movement of molecules in and out of the more concentrated region and into the lesser concentrated one is till the concentration is equal.
3. Such a process does not require any input of energy.
4. A concentration gradient itself is a form of stored energy, which is utilized as concentrations tend to equalize.
5. The directional movement as a result of diffusion along a gradient is passive and continues this way till the molecules are dispersed evenly.
6. Non-polar and small molecules can diffuse freely across the cell membranes.

The rate of diffusion could be affected by many factors such as :

1. Size of molecules – large particles have a greater resistance in a fluid medium
2. Temperature
3. Rate of diffusion is higher if the concentration gradient is higher – the steepness of the gradient