1. Chapter 3
Cell Structure

2. Chapter 3A
Cell Membranes

3. A. Describing Cell Membranes
I. Cell Membranes
A. Describing Cell Membranes

4. Cytology
The study of cells

5. A. Describing Cell Membranes
1. Outer boundary of the cell 2. Senses and responds to changes in the environment

6. A. Describing Cell Membranes
Protects cell from harmful substances
Porous - allows needed materials into the cell

7. A. Describing Cell Membranes
3. Fluid mosaic model
Phospholipids
Hydrophilic
Hydrophobic
Lipid bilayer
“bi-” means two

9. A. Describing Cell Membranes
4. Selectively Permeable

10. Selectively Permeable
A selectively permeable membrane allows certain molecules to pass through the membranes and others to not pass through

11. B. Transport Across the Membrane
I. Cell Membranes
B. Transport Across
the Membrane

12. B. Transport Across the Membrane
Passive transport
a) moves substances through a membrane without the use of the cell’s own energy.

13. B. Transport Across the Membrane
Passive transport
b) 2 types
* diffusion

14. Diffusion
The movement of molecules from a place where there are many of those molecules to a place where there are few of them

15. Diffusion

16. B. Transport Across the Membrane
Passive transport
b) 2 types
* diffusion
* osmosis

17. Osmosis
The diffusion of water through a selectively permeable membrane

18. Osmosis

19. B. Transport Across the Membrane
2. Active transport a) requires the cell to use its own energy to move substances through a membrane.

20. Transport Comparison Passive Transport Active Transport
Molecules move from higher to lower concentration
Does not require the cell to use energy
Molecules move from lower to higher concentration
Requires the cell to use energy