1. Today’s Data Here
Objective Here!

2. Brainteaser
Where do you find roads without vehicles, forests without trees, and cities without houses?

3. Bell Work
Which numbered organelle produces ATP and is called the Powerhouse of the cell?
A) 1
B) 7
C) 9
D) 13

4. Let’s Review

5. Maintaining control of the internal environment
The plasma membrane

6. Today you will learn The structure of the plasma membrane
How the plasma membrane functions as a semi-permeable membrane

7. What is the Plasma Membrane?
The membrane separates the organelles of the cell from the outside environment
It is made of a double layer of phospholipids and embedded proteins.

8. What does the plasma membrane do?
Controls what enters and leaves the cell.
Nutrients
Waste
It is said to be selective permeability (Everything CANNOT enter the cell)
Water can freely enter and leave the cell
Maintains homeostasis

9. The plasma membrane acts as a gatekeeper.

10. What is the plasma Membrane made of?
There are 3 types of lipids (fats)
Phospholipids
Glycolipids
Cholesterol
Proteins
Integral (glycoprotein)
Peripheral

11. Structure of plasma membrane
Made of lipids (fats) with a phosphate head
Lipid portion is 2 fatty acid tails. The tail is hydrophobic: does NOT like water
Phosphate head is hydrophilic: it DOES like water.
phospholipid

12. Fluid Mosaic Model Cholesterol embedded in membrane keeps it fluid
The bi-layer is known as the Fluid Mosaic Model, because proteins embedded in the membrane can move

13. Fluid Mosaic Model
Here is what a phospholipid bi-layer looks like as a sphere

14. How do materials move into and out of the cell?
Materials must move in and out of the cell through the plasma membrane.
Some materials move between the phospholipids.
Some materials move through the proteins.

15. How do materials move into and out of the cell?
Some proteins span membrane and determine which molecules can enter or leave. These are transport proteins.
Other proteins on the surface act as receptors

16. The Proteins of the Plasma Membrane
1) Channel Proteins
2) Carrier Proteins
3) Enzymatic Proteins
4) Receptor Proteins
5) Cell Recognition Proteins

17. 1) Channel Proteins
Have channels that allow molecules to move from an area of high concentration to an area of low concentration. NO energy is used

18. 2) Carrier Proteins
Carrier Proteins – combine with a molecule to help it move across the membrane

19. 3) Enzymatic Proteins
– Carry out metabolic reactions

20. 4) Receptor Proteins
Receptor Proteins– Have a binding site for a specific molecule.

21. 5) Cell Recognition Proteins
Marker Proteins–extend across the cell membrane and serve to identify the cell. The immune system uses these proteins to tell friendly cells from foreign invaders. They are as unique as fingerprints.
They play an important role in organ transplants. If the marker proteins on a transplanted organ are different from those of the original organ the body will reject it as a foreign invader.

22. The plasma membrane is said to be
Selectively Permeable

23. Let’s Review!!! What is the function of the cell/plasma membrane?
What is the membrane made of?
The membrane is said to be ________________
What is the name of the model?
How can molecules enter the cell?

24. Now build your own!

25. How well did you do today?
Cell membranes are constructed mainly of:
A. lipid bi-layers
B . Protein pumps
C. carbohydrate gates
D. chloroplast