1. Cell Transport 1. What is the purpose of the cell membrane? 2. Why would we need to regulate what goes in and out of the cell? 3. What are some things that might need to be transported into or out of the cell?

2. Structure of the Plasma Membrane o Phospholipid Bilayer: two layers of lipids with a phosphate head Phosphate head is hydrophilic Lipid tail is hydrophobic There is a watery environment inside and outside the cell, so the phosphate heads align towards the water. o Proteins – passageways through the plasma membrane Some act as cell markers, others as channels

4. Proteins Carbohydrate Chains Phosphate HeadProtein Channel Lipid Tail

5. Structure of the Plasma Membrane (cont) The plasma membrane is selectively permeable – only certain substances are allowed to pass through it.

6. Types of Cell Transport P ASSIVE T RANSPORT A CTIVE T RANSPORT  Movement of a substance through a cell’s membrane without using any energy  Moves from high concentration to low concentration  Three types : diffusion, osmosis and facilitative diffusion  Movement of a substance through a cell’s membrane using any energy  Moves from low concentration to high concentration  Two types : endocytosis and exocytosis

7. PASSIVE TRANSPORT

8. 1. Diffusion the movement of particles through the plasma membrane from an area of high concentration to an area of low concentration o Concentration - the amount of solute in a solution Solution – mixture of solutes and solvents Solute – substance dissolved in another substance Solvent – a substance that does the dissolving o Diffusion will occur until equilibrium is reached (the concentration of the substance is the same)

9. o Example: in lungs, oxygen diffuses into the bloodstream because there is less oxygen in the bloodstream

10. 2. Facilitated Diffusion the transport of specific particles through a membrane by a channel protein.

11. 3. Osmosis the diffusion of water molecules through a selectively permeable membrane from an area of high water concentration to an area of low water concentration

12. Isotonic Solution – the concentration of solutes is the same inside and outside of the cell The cell and environment are at equilibrium

13. Hypotonic solution – the solution with the higher solvent (water) content Water moves into the cell and the cell will swell

14. Hypertonic solution – the solution with the higher solute concentration Water moves out of the cell and the cell will shrink

15. ACTIVE TRANSPORT

16. 1. Endosytosis process by which a large macromolecule enters a cell. Extracellular vesicle fuses with the plasma membrane, the membrane pinches inward, the vesicle is transported into the cell. ◦ Two types:  Pinocytosis – engulfing a liquid (cell drinking)  Phagocytosis – engulfing another cell or organic matter (cell eating)

17. Endocytosis

18. 2. Exosytosis large macromolecule leaving a cell. Intracellular vesicles migrate to the plasma membrane, fuse with it, and release the contents out into the cell

19. Exocytosis