Question

What is the biological importance of diffusion to cells/organisms?

Answer 1

Diffusion:

Diffusion is the movement of gas or solute molecules from a region of higher concentration to a region of lower concentration until they are equal.

Diffusion is important to organisms because it is the process by which useful molecules enter the body cells and waste products are removed.

examples:

The intestines

Digested food molecules (amino acids, glucose) move down a concentration gradient from the intestine to the blood. Waste products such as carbon dioxide or urea travel by diffusion from body cells into the bloodstream.

The lungs

Oxygen moves from high concentration (in the air sac) to a lower concentration (in the blood). Carbon dioxide moves from high concentration (in the blood) to a lower concentration (in the air sac).

This can be seen in the following diagram.