1. Cell Boundaries and Movement

2. Cell Barriers Cell membranes
Structure: contain a flexible lipid bilayer with imbedded protein molecules and carbohydrate molecules
Function: Substances move across the cell membrane through
A.) lipid bilayer
B.) protein channels
C.) assistance of protein
molecules
D.) Processes of endocytosis
and exocytosis

3. Cell Barriers Cell Walls
Structure: made mostly of tough carbohydrate fiber called cellulose
Function: Cell walls support and protect cells; cell walls are porous and allows substances to move through easily

4. Types of Movement Through Cells
A.) Diffusion B.) Osmosis C.) Facilitated Diffusion D.) Active Transport

5. Diffusion
Substances move across the cell membrane from areas of high solute concentration to areas of low solute concentration until equilibrium is reached
No energy required
Substances continue to move back and forth across the membrane once equilibrium is reached

6. Osmosis The diffusion of water across a cell membrane
Types of osmotic solutions
Hypotonic
Isotonic
Hypertonic

7. Concentration
Concentration of a solution is the mass of solute in a given volume of solution, or mass/volume A Solute is a substance that is dissolved in a solvent to make a solution

8. Which way will the water move?

10. Hypotonic Solution
Animal Cell
the solution has a lower solute concentration than the cell so water moves into the cell causing plant cells to swell and animal cells to swell and burst
Lower solute concentration outside cell
Lower solute concentration
Plant Cell
Lower solute concentration outside cell

11. Isotonic Solution
Animal Cell
The concentration of solutes is equal inside and outside the cell so water moves across the membrane in both directions maintaining cell size
Equal solute concentration inside and outside cell
Plant Cell
Equal solute concentration inside and outside cell

12. Hypertonic Solution
Animal Cell
The solution has a higher solute concentration than the cell so water moves out of the cell and into the solution causing the cell to plasmolyze
higher solute concentration outside cell
Plant Cell
higher solute concentration outside cell

13. CELL MEMBRANE
Lipid layer 1
Proteins
Lipid layer 2

14. Facilitated Diffusion
A) Substance specific protein channels allow movement of molecules such as glucose to move across the membrane in either direction
B) Substances still move high concentration to low concentration and no energy is required

15. REMEMBER: Requires ATP Energy! Active Transport Characteristics:
Movement of substances is against the concentration gradient
Energy is required !
Types of Active Transport
Molecular transport
Endocytosis
Exocytosis
REMEMBER:
Requires ATP Energy!

16. Active Transport – Molecular Transport
Molecular transport: Protein molecules act like energy requiring pumps to move molecules and ions across membranes

19. I NEED THOSE GREEN THINGS!

20. Active Transport – Endocytosis
Endocytosis – Materials are taken into the cell by means of forming in the cell membrane. The pocket becomes a vacuole inside the cell.

21. ENDOCYTOSIS

22. ENDOCYTOSIS

23. Cool video showing Endocytosis
Paramecium EATS 2 amoebas

24. Exocytosis

26. Active Transport – Exocytosis
Exocytosis – EXPEL WASTES FROM CELL Wastes moved out of the cell when a vacuole fuses with the cell membrane

27. VIDEO of EXOCYTOSIS