1. Cell Transport
Ms MacCormack

2. There are two main types of transport that occur across a cell membrane:
Passive Transport
Active Transport

3. Passive Transport
Does NOT use energy
Moves substances from high to low concentration.
Moves “with” the concentration gradient.
Concentration gradient = when “things” are not distributed
equally; all bunched in one place
Makes things more even.

4. Types of Passive Transport
Diffusion
Osmosis
Facilitated Diffusion

5. Diffusion
Movement of small particles from high to low concentration
Does not use energy  Passive Transport
Happens because things are uneven.
End goal = reach a dynamic equilibrium
Dynamic equilibrium = things are distributed equally on both sides of a membrane and equal numbers of particles move in and out of the cell at equal rates

6. Osmosis
Diffusion of water
Does NOT use energy  passive
Moves water from area of high to low concentration.
Happens until dynamic equilibrium is reached.

7. Facilitated Diffusion
Uses a protein to help move substances across the membrane.
Does NOT use energy
Moves particles from an area of high to low concentration
Happens until dynamic equilibrium is reached.

8. Active Transport
Uses energy to move substances across the membrane.
Moves substances from low to high concentration (against the concentration gradient)
Makes things more uneven..