1. Getting In and Out of Cells
Cellular Transport
Getting In and Out of Cells

2. Introduction
Homeostasis--keeping the proper conditions inside, regardless of the conditions outside
Example: We keep the inside of our bodies not too hot and not too cold, but “ Just Right.”
The cell membrane controls what goes in and what goes out of each cell.

3. Movement through a cell membrane depends on three things:
1. the size of the molecule
2. the path that the molecule takes (slipping through the lipid fence or going through a protein “gate”)
3. whether or not energy is used

4. Passive Transport
Passive Transport: Movement of substances through the cell membrane without the input of energy
YOU DON’T NEED THIS ATP

5. Equilibrium is reached.
Diffusion
1. Diffusion: Molecules move from an area of high concentration (lots of molecules) to an area of low concentration (few molecules) until they spread out evenly:
Equilibrium is reached.

6. Example Perfume in a room Food coloring in water
Oxygen diffuses from lungs into red blood cells

7. Osmosis
2. Osmosis: The diffusion of WATER across a selectively permeable membrane

8. Selectively Permeable Membrane
allows some things to pass through, blocks others

9. Example Water moving in and out of animal cells and plant cells

10. Facilitated diffusion
3. Facilitated diffusion: Large molecules diffuse with the help of
transport proteins (larger openings in the cell membrane: the gate)

11. Example
Glucose moving into a cell through the transport protein “gate”