1. Diffusion and Osmosis

2. Diffusion
Solute molecules moving from an area of high concentration to an area of low concentration
Random motion drives diffusion
Movement is based on kinetic energy (speed), charge, and mass of molecules
Equilibrium is reached when there is an even distribution of solute molecules
(water) 2 3 1 4

3. Cell Membrane
Semipermeable - Some things can get through and some things cannot

4. Why is the cell membrane semi-permeable?
To complete necessary functions in the cell:
Bring oxygen into the cell, and remove carbon dioxide.
Brings water into the cells.
Removes waste from cells.
Prevents some things from coming into the cell.

5. Osmosis Diffusion of water through a semi-permeable membrane
Semi-permeable: permeable to solvents (WATER), but not to large molecules
High [water] to low [water]

6. Osmosis Dissolved molecules (i.e. glucose, starch) are called solutes
REMEMBER:
Water = solvent
Glucose, Starch = solutes

7. Hypertonic- means water moves from the cell to the environment

8. Isotonic- means water moves equally between the cell and the environment

9. Hypotonic – means water moves from the environment to the cell

10. Osmosis in Living Cells
Cellulose in cell wall

14. Movement of Substances across
Cell Membranes
Cell membrane – dual function
Stops some materials
Allows exchange of other materials

15. Transportation of Molecules
Passive Transport
Does not require energy
follows the concentration gradient from high to low

16. Transportation of Molecules
Active Transport
Needs energy to move particles
Moves against the concentration gradient from low to high

18. % H2O
10% Solute
10% solute

19. % H2O
40% Solute
10% solute

20. % H2O
10% Solute
40% solute

21. Photosynthesis
The process in which plants use sunlight to convert carbon dioxide and water into oxygen and glucose (sugar).

22. Respiration
C6H12O6 + 6O CO2 + 6H2O + released energy
The process in which animals and plants use oxygen and glucose to release energy and release water and carbon dioxide.