1. I.The Cell Membrane Controls what enters and leaves the cell
Provides structure and support
Most cell membranes are made of a double layered sheet called a phospholipid bilayer.

2. The Cell Membrane Proteins Protein Lipid bilayer channel
Figure 7-15 The Structure of the Cell Membrane
Section 7-3
Outside
of cell
Carbohydrate
chains
Proteins
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
A semi permeable membrane means that some substance can pass across the membrane and others cannot. The cell membrane is a semi-permeable membrane
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3. Solution vs. Solutes
A solution is a liquid mixture of two or more substances and are evenly mixed.
The dissolved substance is called the solute.
A solvent dissolves the solute
Solvent + Solute = Solution
Examples: Salt water, sugar water,

4. Passive Transport
Transport across the cell membrane that does not require energy.

5. Diffusion
Diffusion is the tendency of molecules to move from an area of high concentration to an area of low concentration.

6. Diffusion
Molecules move from an area of high concentration to an area of low concentration.

7. Diffusion
A semi permeable membrane means that some substance can pass across the membrane and others cannot.
The cell membrane is made up of a semi-permeable membrane

8. Diffusion
Some molecules, such as water, can cross the cell membrane by diffusion.

9. Diffusion
When the concentration of a solute is the same through out a solution, the system has met equilibrium.

10. Diffusion
Cells constantly maintain equilibrium in any system they are in and molecules are always passing in and out of the lipid bilayer even when equilibrium is met.
Equilibrium- When the concentration of a solute is the same through out a solution, the system has met equilibrium.

11. Example of Diffusion

12. Osmosis
Osmosis is the diffusion of water through a selectively permeable membrane.

13. Review Osmotic Pressure video
Effect when cell is placed in…
ISOTONIC
HYPO TONIC
HYPERTONIC

14. Hypotonic: The solution has a HIGHER concentration of water than the concentration of water inside the cell therefore water will GO INTO the cell and the cell increases in size.
Isotonic: The solution has an EQUAL concentration compared to the inside of the cell therefore no water would move in or out and the cell would remain the SAME size and shape.
Hypertonic: The solution the cell is has a LOWER concentration of water than the concentration of the water inside the cell therefore water would MOVE OUT the cell and the cell would shrink

17. Active Transport

18. Active Transport
Material moves from an area of lower concentration to an area of higher concentration in a process called active transport.
Active transport is the movement across the cell membrane that requires energy in the form of ATP.

19. How is this different than passive transport?

20. Forms of Active Transport
Endocytosis- the process of taking in material into the cell by means of infoldings, or pockets, of the cell membrane.

22. Forms of Active Transport
Exocytosis- is the removal of large amounts of material from the cell.

23. Two Methods of Transport
Passive Transport
Active transport
Without Energy
With Energy
Diffusion
Osmosis
Endocytosis
Exocytosis