1. Cells
Chapter 3

2. Cells Basic organizational structure of the human body
About 75 trillion cells in our bodies
Can look and function quite differently

3. Differentiation
When cells specialize
Specialize in function and form

4. Cells

5. Typical animal cell
Many organelles with distinct roles (ex: mitochondria, nucleus, etc.)

6. Cell (plasma) membrane
Important in physiology
Allows stuff in and out of the cell, so the cell can perform it’s function
But, it’s selectively permeable, meaning that only certain stuff can go in and out

7. Cell (plasma) membrane
Phospholipid bilayer
Embedded proteins

10. Movement across cell membranes
Materials must cross the membrane
Metabolism of the organism occurs within the cell.
Important molecules such as carbon dioxide, sugars, oxygen, and nutrients must move into and out of the cell.

11. Movement across the membrane
Can be passive- no input of energy
Simple and facilitated diffusion
Osmosis
Or active- necessitates energy to move stuff
Active transport
Endocytosis
Exocytosis
Transcytosis

12. Simple diffusion
Movement of material from an area of higher to lower concentration

13. Simple diffusion

14. Simple diffusion

15. Simple diffusion
Selectively permeable

16. Factors that affect the rate of diffusion
Concentration
Temperature
Size of molecule
Charge of molecule

17. Osmosis
Same thing as simple diffusion, just with water

18. Osmotic pressure
Force exerted on a selectively permeable membrane due to osmosis

19. We want the concentration of sugar and water to be equal between the two containers
There’s too much sugar on the right side
The only way to equalize is to move water (sugar is too big to pass through)

20. Tonicity
Degree to which a solution’s solute concentration causes water to move into or out of cells
Solution = Solvent Solute
- Hypotonic
- Hypertonic
- Isotonic
Salt water
water

21. Solution types

22. Facilitated diffusion
Maybe the molecule is too big (sugars, salts)
Transmembrane proteins can come to the rescue!
Still moving from a higher to a lower concentration
No energy required

23. Active transport
Particles are moved against the concentration gradient
Requires energy!!!
Actively climbing against gravity requires energy.

24. Active Transport
Movement of a substance against the concentration gradient
Uses a carrier protein and energy (ATP)
Examples: ions, amino acids, and sugars

25. Endocytosis Bulk transport
Movement across the membrane and into the cell using vesicles
Requires energy

26. Exocytosis Bulk transport
Movement across the membrane and out of the cell using vesicles
Requires energy

27. Transcytosis
Endo, followed by exocytosis
Moves substances rapidly