1. Opening Questions:
1. What is the 1st major part of the cell we talked about?
2. Name one thing that it does for the cell.
3. Name the three types of proteins that make up the Cytoskeleton.

2. Learning Outcomes
Recognize the key components of the cell plasma membrane.
Explain how the plasma membrane regulates the passage f molecules into and out of the cell.
Describe the diverse functions of proteins embedded in the palsma membrane.

3. The Three Major Parts of the Cell

4. 2. PLASMA CELL MEMBRANE

5. It is the protective outer covering of all cells
It gives the cell its distinct shape
Acts as a fence around the cell
Its like a PICKET FENCE

6. Must stay in a SEMI-FLUID state in order to be
SEMI-PERMEABLE or SELECTIVELY PERMEABLE

7. SELECTIVELY or SEMI-PERMEABLE
1. Allows certain substances in
Example---Nutrients
2. Allows certain substances out
Example----Waste
3. Keeps certain things in
Example----Organelles
4. Keeps certain things out
Example---Disease and foreign objects

8. A. 3 Molecules of the Cell Membrane

9. Has a head that is made of phosphate “Hydrophillic” Water loving
1. PHOSPHOLIPID MOLECULE
Has a head that is made of phosphate
“Hydrophillic”
Water loving
Because it can dissolve in water

10. It has a tail that is made up of a lipid “Hydrophobic” Water fearing
Because it does not dissolve in water
Lipids will dissolve in other lipids

12. Because the tail is afraid of H2O and there is H2O surrounding your cells….
Extracellular fluid outside each cell and
The cytoplasm (made of water and various molecules) in each cell
How do the phospholipid molecules line up?

13. They form a DOUBLE layer with the tails facing each other and the heads on the outside and inside.

15. Phospholipid molecules act as the pickets of the fence
Little molecules can pass through them by dissolving in lipids.

16. 2. PROTEINS
Proteins are used to identify large molecules or molecules that can not dissolve in lipids. Proteins decide whether the larger molecules can come in or not

17. 2 Types of Proteins: Integral Proteins----
Proteins that go all the way through the membrane
2. Peripheral Proteins---
Proteins that are only on one side of the membrane

18. Proteins act as the gate of the fence

19. Membrane Proteins
a. Channel Proteins b. Transport Proteins c. Cell Recognition Proteins d. Receptor Proteins e. Enzymatic Proteins f. Junction Proteins

20. a. Channel Proteins
Channel Proteins form a tunnel across the entire membrane… They allow only one or a few specific types of molecules to enter or exit the cell.

21. EXAMPLE
Aquaporins--- Channel proteins in the kidney… Allows water molecules in or out of the cell Without them we would dehydrate

24. b. Transport Proteins
Transport Proteins often bond with a molecule or ion and help carry across the membrane. They usually use cell energy to help the molecule/ion across

25. EXAMPLE
They help sodium and potassium to cross the membrane of the nerve cell (neuron) Without them, nerve impulses would be impossible.

27. c. Cell Recognition Proteins
Cell Recognition Proteins are glycoproteins that are used to enable our bodies to distinguish between our own cells and that of another organism.

28. More Info
Found especially on white blood cells Allow them to distinguish between the pathogens that invade our body and our own cells

30. d. Receptor Proteins
Receptor Proteins are proteins that change their shape along the membrane which allows a molecule known as a SIGNAL MOLECULE to bind to it.

31. The bonding of a signal molecule causes the receptor protein to change shape. When the receptor protein changes shape the cell is able to respond to a certain molecule.

32. EXAMPLE
Hormone insulin binds to the receptor proteins in liver cells. When they bind to the membrane they allow the liver cells to store glucose.

34. e. Enzymatic Proteins
Enzymatic Proteins are proteins that are directly involved in the metabolic processes of the cell. These proteins can attach to various cell membranes

35. Example
DNA helicase--- Enzyme that causes DNA to unzip (break apart) so it can replicate (duplicate)

37. f. Junction Proteins
Junction Proteins are proteins will be discussed later. But they assist in cell to cell adhesion and communication

38. More Info
The cells in the bladder use junction proteins to adhere to one another when the bladder fills with liquid waste (urine).

40. Helps to give the cell membrane its shape
3. CHOLESTEROL
Another lipid
Helps to give the cell membrane its shape

41. Cholesterol acts as the posts of the fence

43. 3 major molecules(REVIEW)
1. PhosphoLIPID—
Pickets—small things in & out
2. Proteins---
Gates---lets big things in & out
3. Cholesterol---LIPID
Posts---structure

44. The cell membrane is considered a bilayer or a DOUBLE layer of
PROTEINS and
LIPIDS

45. Scientists way of describing the cell membrane
The Fluid Mosaic Model

46. FLUID---Because the membrane must stay semi-fluid to be selectively permeable
MOSAIC---Because it is made up of many different molecules but is one structure

47. Wrap It Up

48. The plasma cell membrane is used as protection for each cell--give it distinct shape
It stays semi fluid---allowing it to be selectively permeable

49. This means it selects what goes in and out and
what stays in and out
The plasma membrane is made up of 3 main molecules:
Phospholipid molecules
Protein molecules and
Cholesterol molecules

50. For this reason the plasma (cell) membrane is considered a DOUBLE layer of PROTEINS and LIPIDS.