1. Structure
Made of
Composed of
Has
Function
Can
Used for
Allows for

3. Structure or Function Selectively transports Flexible
Selectively permeable
Controls what enters and leaves cell
Fluid mosaic like in that the molecules can move past each other
Communicates with other cells through cell signaling
Hydrophilic on the outside, hydrophobic inside
Serve to identify other cells
and molecules
Function
Provides support and protection
Is made of cholesterol,
phospholipid, protein,
carbohydrate molecules
Secretes cell products
Excretes waste products
Maintains a barrier from the outside environment
Helps to maintain cellular homeostasis
Provides channels for molecules to move through

4. Vocabulary for today
Semipermeable/Selectively Permeable/
Selective Permeability
Cell Membrane/ Plasma Membrane
Phospholipid Molecule
Fluid Mosaic Model
Receptor
Homeostasis
Transport

5. In order to survive a cell must :
1. Be Protected from the outside environment
2. Interact with and respond to changes in the outside environment

6. KEY CONCEPTS : The cell membrane regulates what enters and leaves the cell.

7. The cell membrane is important in maintaining a homeostatic balance between the cell and its environment.

8. The Cell Membrane has three major functions Protective boundary
Regulate movement of materials into and out of the cell
3. Communicate with other cells
cell membrane
outside cell
inside cell

9. What do you think gives the membrane its ability to carry out these functions?
a. Size
b. Shape
c. Structure
Structure

10. Cell Membrane Structure
The cell membrane is made of different types of molecules:
Phospholipids
Cholesterol
Proteins
Carbohydrates
cell membrane
protein
cholesterol
carbohydrate
chain
protein channel

11. Membrane Molecule and their Functions

12. 3 Parts of a Phospholipid: Phosphate molecule Glycerol
1. Phospholipids
#1 molecule – makes up 75% of the cell membrane
3 Parts of a Phospholipid:
Phosphate molecule
Glycerol
2 Fatty acid chains

13. The phospholipids are arranged into a bilayer Phospholipid Bilayer
Hydrophobic and Hydrophilic Parts of Membrane

14. 2. Cholesterol (lipid)
Provides strength to the membrane by making it flexible

15. 3. Proteins Transport materials across the membrane
Anchor the cytoskeleton
Serve as chemical receptors
Enzymes needed to speed up chemical reactions

16. 4. Carbohydrates Identification tags
Provides chemical communication between cells

17. ‘Fluid Mosaic Model”describes the membrane structure

18. The Cell Membranes’ most important property is
Selectively Permeability – allowing select substnaces to pass through .

19. Selective Permeability allows the cell to maintain
Homeostasis- a steady internal state regardless of changing
conditions outside the cell.

20. Charge (positive, negative, neutral)
Whether a molecule passes thru the membrane depends on its
Size
Charge (positive, negative, neutral)
Concentration differences inside/outside of cell
If a transport molecule is available
Shape

21. Examples of General Rules of Movement Examples:
Small, non polar molecules ______________________
Small, polar molecules__________________________
Large molecules ______________________________

22. Small, non polar molecules move easily through on their own
Small, polar molecules__________________________
Large molecules ______________________________

23. Examples of Rules of General Movement:
Small, non polar molecules move easily through on their own
Small, polar molecules must be moved through with the help
of transport proteins
Large molecules ______________________________

24. * Small, non polar molecules – easily move through membrane on their own.
* Small, polar molecules - moved through membrane by
transport proteins
Large molecules Moved across membrane inside vesicles

25. Cell Signalling
Key Idea: Cells use chemical molecules to communicate with each other and their outside environment
Examples of “chemical signals”:
* Hormones
* Insulin
* Medicines
* Growth Factors
* Neurotransmitters
(chemicals that stimulate the nervous system)
* Chemicals that make food smells, flower scents

26. Cell Signalling The chemical “messenger” is called a ligand
Cell Signalling The chemical “messenger” is called a ligand. The chemical “receiver” is called a receptor and is often a protein molecule.

27. When a ligand and receptor bind they change shape which causes a series of changes in the cell.

28. .
Two types of receptors.
Intracellular receptors – inside the cytoplasm

29. .
Two types of receptors.
Intracellular receptor – inside the cytoplasm
Membrane receptor – inside the membrane

30. Cell Communication is Vital to keeping the body ALIVE!
STRESS RESPONSE

31. Diseases caused by Cell Membrane Abnormalities
Cystic Fibrosis – defective protein channel in the membrane which doesn’t allow calcium into cell and results in an excessive production of fluid in lungs and digestive system. Makes it hard to get oxygen and food.
Alzheimer’s – stiff fatty acids used in brain cell membranes
Diabetes- Lack of insulin receptors in membrane