1. How things get in and out of cells
Cell Transport
How things get in and out of cells

2. Cell membrane - Structure
A phospholipid contains-
one head; negatively charged phosphate group that is hydrophilic (water-loving)
two tails of fatty acid chains that are hydrophobic (water fearing)

4. Made of a phospholipid bilayer
The Cell Membrane
Made of a phospholipid bilayer
regulates what passes in/out
Supports and protects
Selectively permeable – only certain things pass through.
5 nm thick

6. Cell membrane features
The fluid mosaic model
fluid in nature  cell mobility
Within mem. are various proteins for:
enzyme activity,
cell attachment,
communicating with other cells,
Trans. of substances in and out

8. Transport Moving materials in/out of cell Two categories
Passive: doesn’t require ATP from cell
Active: requires ATP

9. Passive Transport 1. Simple Diffusion
net movement of substances (liquid or gas) from an area of higher concentration to area of lower conc.

10. Passive Transport
1. Simple Diffusion

11. Passive Transport
1. Simple Diffusion

12. Passive Transport 2. Facilitated Diffusion
Trans. larger molecules with the help of a dedicated transport protein gate
Protein gate made for specific molecule passage.

13. Passive Transport
2. Facilitated Diffusion

14. Passive Transport 3. Osmosis
Diffusion of water across a semi-permeable membrane.
To permeate = to go through

15. Passive Transport 3. Osmosis
Hypertonic: Solution having a high conc. of solute.
Hypotonic:   Solution having a low conc. of solute.
Isotonic:   Both solutions have equal solute conc.
Review: Solution= solute+solvent
This difference (Δ) of conc. of molecules across a space is called a Concentration Gradient

16. Passive Transport

17. Passive Transport

18. Passive Transport Animal Plant Lysis Equilibrium Plasmolysis
Turgid Flaccid Plasmolysis

19. Passive Transport

20. Passive Transport Lab
Question: Can osmosis occur through the membrane of a shell-less chicken egg?
Hypothesis: (write)
Procedure: (write) Materials: Vinegar, 6 eggs, bucket, 150 ml beakers, water/sink, paper towels, electronic balance, syrup,
Data: (record)
Analysis/Conclusion: (write)

21. Active Transport
Transporting of molecules against a concentration gradient (from regions of low conc. to regions of high conc.) with the aid of proteins in the cell mem. and energy from ATP
Analogy: Pushing a rock uphill

22. Cell membrane pumps Active Transport
Carrier proteins that move sub. from low to high conc.
Ex: Sodium-Potassium pump
3 Na+ pumped out of the cell
2 K+ pumped into the cell

23. Active Transport
Cell membrane pumps
(4)
(3)

24. Endocytosis Active Transport
Importing larger quantities of materials by infoldings of the cell mem.
A. phagocytosis – “cell eating”; cell mem. surrounds food – buds off a vacuole. Lysosomes then secrete enzymes into vacuole to digest food.
B. pinocytosis – “cell drinking”; smaller infoldings allows droplets of liquid to enter.

25. Active Transport
Endocytosis

27. Exocytosis Active Transport Large quantities of sub. exiting cell
Dumping of excretions or wastes to outside
Secretion of products needed elsewhere (ex: new proteins, hormones, etc.)

28. Active Transport
Exocytosis

29. Quizlet on Transport