1. Introduction to...
Cell Transport

2. Semi-Permeable Membrane
The cell membrane is semi-permeable
Semi-permeable-only certain things can pass through (permeate) it
Smaller molecules can pass through.
Larger molecules and charged molecules cannot.

3. Passive vs. Active Transport
PASSIVE= **No energy (ATP) needed for movement of certain particles across the membrane in/out of cell.
Particles (molecules and ions) move from HIGH to LOW concentration.
“Paddling with the current.”
Types of passive transport
Diffusion
Osmosis
Passive facilitated diffusion

4. Which container has the highest concentration of solutes?

5. Diffusion Move from high to low concentration
Occurs until equilibrium is reached.
PASSIVE TRANSPORT, SO NO ENERGY REQUIRED FOR PARTICLES TO DIFFUSE!!!

6. Osmosis Osmosis-diffusion of water
PASSIVE, SO NO ENERGY REQUIRED TO DO THIS!
Water can go through the semi-permeable cell membrane.
High  low
Osmosis animation

7. Hypertonic Environments
Osmosis can occur with water going into OR out of the cell, depending on what type of environment the cell is in.
Hyper= above/higher
Hypertonic- the cell is in a higher solute concentration
i.e. saltwater
Osmosis- water moves OUT
of cell in this environment (highlow).
Shrivel and die.

9. Hypotonic Environments
Hypo = under/lower
Hypotonic- the cell is in a lower solute concentration
i.e. pure water
Osmosis- water will move INTO cell in this environment (highlow)
Swells with water and bursts.
Cell wall prevents plant cells from bursting—like a water balloon in a box

11. Isotonic Environments
Iso = same/equal
Isotonic cell environment- equal solute concentration inside and outside the cell
i.e. pure blood
Water flow in = water flow out
Cells remain the same

12. 100% Water, 0% Salt Pure Water
96% Water, 4% salt Concentrated Saltwater
100% Water, 0% Salt Pure Water
98% Water, 2% Salt Blood

13. Passive Facilitated Diffusion
NO ENERGY (ATP) NEEDED! PASSIVE!
Some particles are too large to pass through the membrane.
Special proteins come to the rescue