1. Cell Surface Area to Volume Ratio
There is a limit to cell size due to volume
Cell surface to volume calculator
As cell volume increases, cell surface area can not keep up.
Think of blowing up a balloon. It may pop!
Therefore, there is a limit to cell size.

2. WHY ARE MEMBRANES IMPORTANT?

3. Mitochondria cell power generator have 2

4. NUCLEUS has a membrane

5. ANIMAL CELLS have a large membrane

6. PLANT CELLS have a large membrane

7. What functions do cell membranes serve for cells?
Protects what is inside
Move substances in/out
Holds substances
Keep the cell from getting too big

8. Phospho- means phosphate-PO4 Lipid means fat
What type of molecules are CELL MEMBRANES made of?
Hydro-water
Phobic-fear
Philic-love
Phospho- means phosphate-PO4
Lipid means fat
AVOIDS WATER!
LOVES WATER! ♥

9. One phospholipid shown 3 ways
Chemical formula of Phosphate
Chemical formula of lipid (fat)
Phosphate( PO4)
Sugar
Lipid (fat)

10. Proteins in the cell membrane
Integral Protein
Peripheral Protein
Channel Proteins
Penetrate both sides of the membrane
On 1 side of membrane
Embed both sides of membrane with a channel (opening)
Receptors may be on the ends of a protein to attract molecules

11. The way a membrane looks Fluid Mosaic Model
Why call a membrane fluid?
The membrane moves all the time
What is a mosaic?
Many pieces put together to make a structure

12. LET’S LOOK AT A MEMBRANE

13. Two forms of Membrane Transport Tutorial You will need Flashplayer
Passive
Active
No energy required
Energy required

14. What type of molecules move passively through a membrane?
Fat Soluble -can dissolve in fats
Since the membrane contains lipids (fat), fat soluble molecules like gases-oxygen, carbon dioxide & steroids, which is a type of fat, move through easily
Let’s watch this tutorial segment

15. Passive transport -Molecules Move Down a Gradient from High to Low

16. What type of molecules need assistance by proteins to move through a membrane?
Water Soluble -can’t move easily
Remember oil and water can’t mix! Since the membrane contains lipids (fat)
So, sugars, proteins, ions (charged particles) and water need help

17. DEFINITION OF SOLUTION
A MIXTURE IN WHICH ONE SUBSTANCE IS DISSOLVED INTO ANOTHER.
SUBSTANCE BEING broken down IS SOLUTE. I.E SALT
SUBSTANCE DOING THE DISSOLVING IS SOLVENT. I.E WATER

19. DIFFUSION A form of Passive Transport Movement of Water, or very Small Molecules
Simple Diffusion- Movement of molecules from high concentration to low concentration
Tutorial
Water uses ____________ to move through the membrane.

20. OSMOSIS Passive Transport
OSMOSIS MOVEMENT OF WATER Molecules
No Energy is Required
Water moves from high concentration low concentration to become equal.
water moves down a concentration gradient.
Let’s see what happens with different cells in solutions

22. Red Blood Cells & Animal Cells
Three types of Osmotic Solutions Can you predict which way water will move?
Hypotonic Solution
Isotonic Solution
Hypertonic Solution
Red Blood Cells & Animal Cells
Plant Cells

24. Sugar Molecules in Water
Which way will the water move? 2. What will happen to the water level in the tube?
Hypotonic
Hypertonic
Sugar Molecules in Water
membrane

25. FACILITATED DIFFUSION NO ENERGY REQUIRED. Uses a transport Protein
Facilitated Diffusion- does not use energy but is assisted by transport proteins in the membrane.

26. MEMBRANE TRANSPORT ACTIVE
ACTIVE NEEDS ENERGY
Molecules move from Low concentration to High concentration of molecules
MOVEMENT of LARGE or CHARGED PARTICLES (IONS) Animation

27. ACTIVE TRANSPORT It needs ? ENERGY!!!! Why?
Going against (up) concentration gradient
Uses 2 different methods
Ion/Protein pumps-for ions, (Charged particles)
Endocytosis- large particles, uses a vacuole

28. Ion-protein Pump

29. Recap of Passive Active Membrane Transport

30. Endocytosis

31. 2 Types of Endocytosis Pinocytosis Cell Drinking Phagocytosis Cell Eating Tutorial