1. Into to Cellular Transport

2. Passive Transport
A molecule or ion that crosses the membrane by moving down a concentration gradient and without using energy

3. Diffusion
The net movement of a substance (liquid or gas) from an area of higher concentration to one of lower concentration.

4. Factors Affecting Diffusion
Concentration – the higher the concentration, the faster diffusion occurs.
Temperature – the higher the temperature, the faster diffusion occurs.
Pressure – the higher the pressure, the faster diffusion occurs.

5. Results of Diffusion
Particles will continue to move until they are distributed evenly.
Particles continue to move and collide, but concentration does not change.
This is called dynamic equilibrium.

6. Osmosis
The passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration.

7. Another definition of Osmosis
Water always moves from where it is most concentrated (has less solute) to where it is less concentrated.

8. Facilitated Diffusion
Some particles are 'helped' through the membrane. This is known as facilitated diffusion. The 'facilitators' are carrier proteins.

9. Active Transport
Unlike passive transport, active transport requires a cell to use or expend energy.
Active transport moves particles against the concentration gradient by use of a pump.