1. Osmosis

2. Osmosis Not all things can move across a cell membrane.
 Permeable: substance can pass through a membrane
Impermeable substance cannot pass through a membrane

3. Osmosis
Selectively permeable membrane - some substance can pass through the membrane while others cannot.
Osmosis: diffusion of water through a selectively permeable membrane.

5. Sugar Water & Selectively Permeable Membrane
If you have a membrane impermeable to sugar, sugar cannot pass through
If it is permeable to water, water can pass
In a beaker, water will pass through the membrane until the concentration of sugar (g/L) is equal on both sides of the membrane.

6. Solution Concentrations
Isotonic: 2 solutions with the same concentration
Hypertonic: solution with higher concentration
Hypotonic: solution with lower concentration

7. Fresh Water and Salt Water Fish

8. Osmosis in Cells

9. Osmotic Pressure
pressure due to the movement of water in/out a cell

10. Facilitated Diffusion & Active Transport

11. Facilitated Diffusion
Protein channels allow certain molecules to cross the cell membrane
Red Blood Cells have channels that help glucose move in/out
channel can only be used by glucose
Substances move in response to concentration gradient
high to low concentrations
Doesn’t require energy

13. Active Transport
Process to move molecules against the concentration gradient
requires energy
carried out by transport proteins or pumps
Transporting Molecules
small molecules and ions (Na, Ca, K)
by energy-requiring pumps

15. Three Types of Transport

16. Endocytosis
taking in material by enfolding, or pockets, of the cell membrane
pockets break loose from the outer portion of the cell membrane
forms a vacuole within the cytoplasm
can take in larger molecules, clumps of food, or whole cells

17. Types of Endocytosis Pinocytosis: uptake of liquids
tiny pockets along the cell membrane
fill with liquid and form vacuoles within the cell
Phagocytosis : “cell eating”
Extension of the cytoplasm surround a particle and package it within a food vacuole

18. Exocytosis release of material
membrane surrounding the vacuole fuses with the cell membrane, forcing the contents out of the cell