1. 7.2 PLASMA MEMBRANE

2. 7.2 THE PLASMA MEMBRANE
WHAT YOU WILL LEARN:
-how a cell’s plasma membrane functions
-the roles of proteins, carbohydrates & cholesterol in the plasma membrane

3. READING QUESTIONS
1-HIGHLIGHT the items in the figure that enter the cell thru pm/CIRCLE those that exit the cell
oxygen
glucose
water

4. READING QUESTIONS 2-EXPLAIN the purpose of phospholipid bilayer?
-allows plasma membrane to survive & function in its watery environment

5. READING QUESTIONS
3-IDENTIFY: CIRCLE one phospholipid—LABEL its head/tail
head
tail

6. READING QUESTIONS
4-DEFINE the role of transport proteins 5-NAME 3 substances that move among the phospholipids of the PM
-move substances through plasma membrane
-proteins/carbohydrates/cholesterol

8. REVIEW -homeostasis: -maintain balance / internal environment
7.2 THE PLASMA MEMBRANE
REVIEW -homeostasis:
-maintain balance / internal environment

9. FUNCTION of the PLASMA MEMBRANE
selective permeability--
-CONTROLS substances ENTER / LEAVE (homeostasis)
WHAT WHEN HOW
*cells must keep proper concentration of nutrients / water / expel waste
-some molecules can cross the plasma membrane --(water)
-others must go through channels --(Na, Ca, etc)
This is like a FISH NET--HOW?
T/P/S: analogy for a cell’s selective permeability

10. FUNCTION of the PLASMA MEMBRANE
FUNCTION of PLASMA MEMBRANE -boundary separates cell & environment -allows water, nutrients & oxygen into cell -allows waste & CO2 out of cell
OUTSIDE CELL
NUTRIENTS
OXYGEN
WATER
CARBON DIOXIDE
WASTE
INSIDE CELL

11. STRUCTURE of PLASMA MEMBRANE
polar head— hydrophilic
…likes water
non-polar tail—
hydrophobic
…repels water

12. STRUCTURE of PLASMA MEMBRANE

13. STRUCTURE of PLASMA MEMBRANE
A- carbohydrate chain
C- polar heads
B- transport  protein
E-cholesterol 
D- non-polar tails

14. STRUCTURE of PLASMA MEMBRANE
B- lipids
C- phospholipid
A- transport protein
F- phospholipid bilayer
D- fluid mosaic model
E- selective permeability

15. FUNCTION of the PLASMA MEMBRANE
DESCRIPTION
SELECTIVE PERMEABILITY
HOMEOSTATSIS
PLASMA MEMBRANE
1-The process of maintaining balance inside a cell.
2-A boundary between a cell & its environment.
3-Feature of plasma membrane that keeps some substances out.
4-Separates prokaryotic & eukaryotic cells from the watery environment in which they exist
5-The quality of a plasma membrane that allows oxygen & glucose to move in
6-Maintained by the plasma membrane

17. Diagram representing the cell membrane.
The above image is from
But I found it at An On-Line Biology Book:

18. STRUCTURE of PLASMA MEMBRANE
-polar heads barrier to water environment in/out of cell -non-polar tails prevent substances dissolve in water from passing thru PM -carbohydrate chain identify chemical signals from environment -cholesterol prevent tails from sticking together, keep membrane fluid -transport protein like tunnels--move materials thru plasma membrane -membrane protein receptors—on outside, send signals to inside of cell anchors—on inside, hold membrane to cell’s internal shape

19. STRUCTURE of PLASMA MEMBRANE
EXPLAIN/DRAW
1-MEMBRANE PROTEIN -create tunnels -PASSIVE 2-TRANSPORT PROTEIN -”pump” substances / ACTIVE

20. STRUCTURE of PLASMA MEMBRANE
EXPLAIN/DRAW
CHOLESTEROL -non polar -keeps PM fluid--prevents fatty acid tails from sticking -maintains homeostasis in cell CARBOHYDRATE CHAIN -help cell identify chemical signals from environment

21. FLUID MOSAIC MODEL
This “MODEL” for the structure of the membrane is called the:
FLUID MOSAIC MODEL
FLUID-
individual phospholipids / proteins move freely within the layer-- like a liquid
MOSAIC-
“pattern” produced by the scattered protein molecules

22. Cell Membranes from Opposing Neurons (TEM x436,740).
Nerve cell
Gap between cells
Cell membrane {
} cell membrane
7nm wide
Nerve cell
AS Biology. Foundation. Cell membranes and Transport