Diffusion

This lesson covers: 

  1. What cells need and what they produce
  2. How diffusion works

What do cells need?

Cells need glucose and oxygen.


These allow cells to release energy during aerobic respiration.

What do cells produce?

Cells produce waste products (e.g., carbon dioxide).


These need to be removed from cells.

Diffusion

Diffusion is the movement of particles from an area of high concentration to an area of low concentration. 


Diffusion does not need energy.


The cell membrane is a barrier, controlling what enters and leaves the cell. Many substances can move through the cell membrane by diffusion, like glucose in the diagram below.

Diagram showing diffusion of glucose through the cell membrane from high concentration outside the cell to low concentration inside the cell.
  • Through diffusion, essential nutrients like glucose and oxygen can enter the cell.
  • Waste products can be expelled from a cell by diffusion.