1. Cell Transport/Membrane

2. Cell Membranes Functions:
Controls what enters and exits the cell to maintain an internal balance called homeostasis
The “bouncer of the cell”, as it is selectively permeable

3. 3. Structure of Membrane: Phospholipid Bilayer
Phosphate head
Fatty acid tails
Hydrophilic = water loving Hydrophobic = water fearing

4. Fluid Mosaic Model
Membrane movement animation

5. What do you think are things the cell needs?
-Water
Sodium and calcium ions
Nutrients
What do you think are things the cell doesn’t need?
-Harmful ions
-Removes excess nutrients if the levels get too high
-Removes waste products

6. Types of Cellular Transport
Animations of Active Transport & Passive Transport
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low
Weeee!!!
Passive Transport
cell doesn’t use energy
Diffusion
Facilitated Diffusion
Osmosis
Active Transport
cell does use energy
Protein Pumps
Endocytosis
Exocytosis
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low
This is gonna be hard work!!

7. Simple Diffusion Animation
Passive Transport:
Diffusion: random movement of particles from an area of high concentration to an area of low concentration until equilibrium is reached

8. Diffusion in our capillaries…
Why does the CO2 leave the blood stream and O2 enter?... Diffusion!

9. Rate of Diffusion
What do you think are the three factors that affect diffusion?
Concentration: The most important factor. The more the concentrated the substances, the faster diffusion occurs.
Temperature: Increased temperature can speed diffusion because of more rapid molecular movement
Pressure: Increased pressure will accelerate molecular movement and speed up diffusion.

10. Facilitated diffusion (Protein Channel) Diffusion (Lipid Bilayer)
Channel Proteins animations
Passive Transport: A B
2. Facilitated diffusion: diffusion of specific particles through transport proteins found in the membrane
Allows certain molecules to cross the membrane
Transports larger or charged molecules
Facilitated diffusion (Protein Channel)
Diffusion (Lipid Bilayer)
HIGH
LOW
Channel

11. Passive Transport:
Osmosis animation
3. Osmosis: diffusion of water through a selectively permeable membrane
*Water will flow “down” the concentration gradient to the side of
the membrane where the water concentration is lower
Water moves freely through membrane while solutes can’t

12. Type of Solutions
Hypertonic: solution has a higher concentration of solutes than inside the cell.

13. Types of Solutions
Hypotonic: solution has a lower concentration of solutes than inside the cell.

14. Types of Solutions
Isotonic: cell environment has an equal concentration of solutes as inside the cell

15. Red Blood Cells
Lysis

16. Plant Cells

17. B C A What type of solution are these cells in? Hypertonic Isotonic
Hypotonic

18. Diffusion and Osmosis in the kidney
Maintaining water balance in the kidney can be inhibited by a diuretic, a substance that causes the kidneys to allow excess water loss. A very common diuretic is caffeine.
Diuretics block the production of the hormone vasopressin, an anti-diuretic hormone (ADH). When the blood has a high concentration of sodium ions, the hypothalamus and pituitary gland (both in the brain) triggers the release of ADH which would tell the kidneys to reabsorb more water to help rehydrate the body.
Basically, caffeine messes up the osmosis in your kidneys! It makes you release more of the water you need to keep. Therefore, your cells become dehydrated.

19. The water “carries” the nutrients across the barrier.
Digestion
Osmosis occurs in both the small and large intestines, with the majority of osmosis occurring in the large intestine. As your body processes food, it moves from the esophagus to the stomach and then to the small intestine. While there, your body absorbs important nutrients via osmosis. As food leaves the small intestine, it travels to the large intestine, and some osmosis can occur here as well.
The water “carries” the nutrients across the barrier.

20. Active Transport

21. Active Transport
Protein Pumps - transport of molecules/ions across the membrane which requires energy.
Transported AGAINST the concentration gradient
Example: H+ ion pump and Na+ K+ pump

22. Active Transport
Endocytosis: very large particles of material are wrapped with plasma membrane and moved into the cell in the form of vesicles.
Phagocytosis = “cell eating”
Pinocytosis = “cell drinking”

23. Endocytosis & Exocytosis animations
Active Transport
Exocytosis: reverse; quantities of material are expelled from the cell without ever passing through the membrane as individual molecules
Hormone release, waste
Endocytosis & Exocytosis animations