1. How many factors are involved in transporting the goods shown from the manufacturer to a store?
What might happen if one of the factors is temporarily unable to function?
How might people who use the product be affected if one factor is not able to function? How might the manufacturer be affected?

2. Cell Transport

3. Thinking question: Why do materials need to move across the PLASMA MEMBRANE?

4. 1. PASSIVE TRANSPORT is the movement of particles across a membrane without requiring energy.
A. Diffusion

5. 2. DIFFUSION - movement of particles from an area of high concentration (more) to an area of lower concentration (less).

6. a. Moving “with the concentration gradient” means going from areas of more, to areas of fewer particles

8. b. DIFFUSION requires no energy
b. DIFFUSION requires no energy. Small molecules move naturally from areas of more to less between the phospholipids.

9. c. After some time of DIFFUSION, a solution reaches DYNAMIC EQUILIBRIUM – concentrations are equal.

10. 3. Water can DIFFUSE easily across the membrane, through special water pores (aquaporins). This is called OSMOSIS.

11. Thinking question: What’s the difference between a SOLUTE and a SOLVENT?

12. a. Water (SOLVENT) will move across a cell membrane to balance the amount of SOLUTE in both sides.

13. Thinking question: Why doesn’t the solute just pass through the membrane? -Solute particles are often too big to pass through the membrane freely.

15. 4. The amount of water in the environment compared to the cell will cause the cell to change shape/size.

16. a. ISOTONIC SOLUTION – the cell’s environment has the same concentration of water and solutes as the cell’s cytoplasm. -Water moves into and out of the cell at even rate.

17. b. HYPOTONIC SOLUTION – the cell’s environment has less concentration of solutes that the cell’s cytoplasm. -Water moves into the cell. This can burst the cell.

18. c. HYPERTONIC SOLUTION – the cell’s environment has higher concentration of solute than cell’s cytoplasm. -Water moves out of the cell. This makes plant cells wilt.

19. Hypertonic
Hypotonic
Isotonic

20. Facilitated Diffusion is another type of passive transport.
Molecules that have difficulty passing directly through the P.M. use transport proteins to help move ions and other molecules across.
B. Facilitated Diffusion
“Facilitate” = to help

21. There are 2 types of transport proteins
Channel proteins create tunnels in the PM to allow molecules to pass
Carrier proteins change their shape to help the molecule cross the PM
Facilitated Diffusion
video

23. The Transporter