1. Insane in the Membrane!

2. Borders?
All Cells are surrounded by a thin, flexible barrier known as the CELL MEMBRANE
Many other cells produce a strong supporting layer around the membrane called the CELL WALL

3. Cell Membrane
The main function of the cell membrane is to regulate what enters and leaves the cell and also provides protection and support for the cell.

4. Do not be fooled!
Even though many cell membranes look like one thin sheet
Nearly all membranes are created by a double layered sheet called a
LIPID BILAYER

5. Why Lipids? Why not?
The two layers of lipids allow for a flexible structure that forms a strong barrier between the cell and it’s surroundings
Lipids are hydrophobic so these create a waterproof lining to the cell as well

6. Cell Walls Found in Plant Cells
Main function of the cell wall is to provide support and protection for the cell.
Most cell walls are made from carbohydrates and proteins.
Cellulose is a common cell wall component

7. Wait one minute?
There are also proteins embedded in the bilayer to allow certain items to enter the cell
These only enter if they are small enough to fit though

8. Semi-Permeable Membrane
Semi-permeable means that certain items can pass through the membrane but only items that are small enough to fit through the “Gaps”

10. Diffusion In a solution and in gaseous form particles move at random
Particles move from areas of high concentration to areas of low concentration.
NO ENERGY REQUIRED
Only requirement is called a CONCENTRATION GRADIENT

11. Diffusion is all about concentration
Molecules will move naturally from an area of higher concentration to an area of lower concentration without the aid of energy.

13. How long will this last?
Diffusion will continue to occur until there is no longer a concentration gradient for the particles to move along.
This point is called EQUILLIBRIUM and is where concentrations are now equal on each side of the membrane

14. Lets take a short quiz!
Take out a sheet of paper and share it with a friend.
Name
Period_____

15. 1. This organelle stores water, carbohydrates, salts and other cell materials
2. This organelle creates lipids and proteins in its inner membranes
3 and 4…Complete the statement
Particles will move at random from __3___ concentration to ____4___ concentration
5. Diffusion will continue until this point is reached

16. Every living cell exists in a liquid environment that it needs to survive
One of the most important functions of the cell membrane is to regulate the movement of dissolved molecules from one side of the membrane to the other.

18. Diffusion activity
Aerosol Spray
Fart Molecules
Perfume
Cookies
Etc…

19. Movement of Water=Osmosis
The diffusion of water through a selectively permeable membrane
Water (A very small molecule) passes easily across most membranes even though many solutes cannot.

20. Water Water is the solvent of life.
Water tries to dissolve anything that can be dissolved and will move to areas where it can be of service.

21. I’ll have a Tonic and Water
Tonic is Latin for “Strength”
Three types of solutions we’ll be talking about
Hypertonic More strong solution
Hypotonic  Less strong solution
Isotonic  Same strength solution

23. Solutions around the cell
A Hypertonic solution
Has more solute than a solution it is being compared to.
Cell has less “Stuff” to dissolve than the solution
In this situation water will move out of the cell and into the area of higher concentration and the cell will shrivel.

25. Solutions An Isotonic solution
Has the same amount of solute as the solution it is being compared to
When this happens the water moves freely into and out of the cell with no change to the cell.

27. Solutions A Hypotonic solution
Has less solute than the solution it is being compared to.
Cell has more “Stuff” to be dissolved than the solution.
When this happens water will rush into the cell to dissolve the solute and increase the mass of the cell. Sometimes too much

29. Hypotonic solutions
Most animal and plant cells are filled with salts, and proteins.
Because of this these cells are prone to bursting when placed in a hypotonic solution.
Trench foot?

30. Quickwrite 10-22 Hypertonic Hypotonic Isotonic
Describe how a cell placed in these solutions will react

31. Review
Diffusion-
Movement of particles “Down” a concentration gradient through semi-permeable membranes
No Energy Required

32. Review
Osmosis-
Movement of water across a selectively permeable membrane
Water moves from areas of low concentration of solute to areas of high concentration of solute
Water is the solvent of life
Hypertonic, Hypotonic, Isotonic

33. Types of Transport There are two types of cell transport:
Passive transport – no energy required, molecules move down the concentration gradient
Active transport – requires energy from the cell because molecules move against the concentration gradient

34. Passive Transport Types of Passive Transport: Diffusion Osmosis
Facilitated Diffusion

35. Factors which affect the rate of diffusion:
Temperature
Size of solute particles
Concentration of solvent

36. Types of Active Transport:
Protein pumps
Endocytosis
Exocytosis

37. Protein Pumps
Some of the Proteins in the cell membrane use energy to actively “Pump” particles across the membrane
Low concentration to High concentration!!!
Uses energy to do this!

39. Transport using membrane vesicles
Endocytosis – cell brings in large molecules
Exocytosis – cell lets out large molecules

40. Endocytosis

41. Endocytosis
Outside of cell
Inside of cell

42. Endocytosis
Outside of cell
Inside of cell
Membrane vesicle

43. Exocytosis

44. Exocytosis
Outside of cell
Inside of cell