1. Cell Transport

2. This is known as diffusion
Particles Move From Areas of Greater or Higher Concentrations to Areas of Lower or Lesser Concentrations
This is known as diffusion

3. HIGH  LOW

4. Animation of How Diffusion Works

5. A Cell Membrane

6. Membranes control what comes in or out of a cell and maintains a balance in the cell called homeostasis

7. Membranes are Selectively Permeable or Semi-Permeable
Some materials can pass through membranes, but others cannot.
Due to the chemical make up of the membrane and the diffusing particles.
The size and charge of the particle determine if a membrane will be permeable to the particle.

8. Animation of Diffusion Through a Semipermeable Membrane

9. MEMBRANES ARE SELECTIVELY PERMEABLE
Some particles diffuse by themselves. Others (ions) have to go through proteins. Others (if they’re too large) will not diffuse at all.
MEMBRANES ARE SELECTIVELY PERMEABLE

10. Diffusion is Important to Cells
See what happens to red blood cells if the water and solute concentrations are not equal in blood cells and surrounding plasma!

11. The diffusion of water in or out of cells is so important, we have a special term for it – osmosis

15. Plant Cells Don’t Rupture Due to Osmosis Because of the Cell Wall

17. The pressure of water in the vacuole of plant cells press up against the cell wall and is called turgor (or tugor pressure)

18. Terms You MUST Know and Understand!
Hypertonic – the SOLUTE concentration is high Hypotonic – the SOLUTE concentration is low Isotonic – the SOLUTE concentrations are equal (at equilibrium)

21. PLANT CELL IN A HYPOTONIC SOLUTION PLANT CELL IN A HYPERTONIC SOLUTION
PLANT CELL IN AN ISOTONIC SOLUTION

23. You can’t always predict which direction solutes move!!!!
It depends if the cell membrane is permeable to the solute!!!!

24. Some unicellular organisms that are very hypertonic to their surroundings have a special vacuole, a contractile vacuole that pumps excess water out of the cell.

25. You can always predict which way water will diffuse
Water moves from hypOtonic solutions TO hypERtonic solutions

26. Ions Pass Through Membranes by Using Proteins
When particles pass through proteins, this is called facilitated diffusion

27. If the Cell Uses Its Own Energy to Transport Materials Through the Cell Membrane, This is

28. In active transport, particles are moved from lower to higher concentrations
This is known as going UPHILL or AGAINST the concentration gradient
Protein pumps in the cell membrane are used in active transport

29. Video on Active Transport

30. When cells do not use their own energy for transport, it’s known as passive diffusion or transport.
Particles are moved down the concentration gradient

31. Very Large Particles or Groups of Particles are Transported by Vesicles

33. Large Particles Move Into Cells by Endocytosis and Out by Exocytosis

34. A Review of Cellular Transport (click on SC, then GO to get this to work)