Movement across cell membranes

Movement across cell membranes

Concentration gradients

The more particles there are in a certain volume, the more concentrated those particles are.

When sucrose is dissolved in water:

• The solute is the sucrose
• The solvent is the water

Diffusion

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

Diffusion is going down a concentration gradient.

Examples

• Oxygen in the lungs diffuse into red blood cells
• A teabag placed in a cup of hot water will diffuse into the water
• Placing food colouring in a liquid will diffuse the colouring
• Cigarette smoke diffuses into the air

Osmosis

Osmosis is the net movement of water molecules from an area of low solute concentration to an area…