1. Transport
Topic 8

2. Transport: Absorption & Circulation of materials
End products of digestion enter body cells

3. Structure of the Cell Membrane:
Cell membrane is the “security guard” of the cell
Semi/Selectively permeable
Regulates movement of materials into & out of the cell
Phospholipid bi-layer

5. The Cell Membrane

6. Phospholipids form 2 layers Phosphate “heads” are hydrophilic
They can touch water outside and inside (cytoplasm) the cell
Lipid “tails” are hydrophobic
They face inward to avoid touching water

8. Fluid Mosaic Model: Model of the cell membrane
Small molecules pass through easily
Ex: amino acids, monosaccharides, glycerol, fatty acids, water & gases
Large molecules don’t pass through easily, they must be broken down
Ex: carbs., lipids & proteins

9. Cell Membrane

10. Methods of Transport: Two Types of Transport Passive Transport
Active Transport

11. 1. Passive Transport:
No energy needed
Diffusion
Osmosis

12. A. Diffusion: Materials move from High  Low Concentration
Continues until equilibrium is reached
Video:

13. Diffusion of Sugar in Water

14. Diffusion of a Dye in Water

15. Diffusion of a Solute Across a Cell Membrane

16. Diffusion of Gases Across a Cell Membrane

17. B. Osmosis:
Diffusion of water
Movement from High  Low Concentration

18. ACTIVE TRANSPORT Energy is required
Materials move from Low  High Concentration

19. Cell engulfs undissolved material
A. Phagocytosis:
Cell engulfs undissolved material

20. Cell membrane pinches in and absorbs dissolved molecules
B. Pinocytosis:
Cell membrane pinches in and absorbs dissolved molecules

21. Endocytosis Exocytosis Materials move into the cell
Materials move out of the cell

22. Passive or Active Transport?
Active Passive

23. Effects of Osmosis on a Cell
Isotonic Solution:
Solution has same concentration of dissolved substances as cell
Hypotonic Solution:
Solution has a lower concentration of dissolved substances than cell
Hypertonic Solution:
Solution has a higher concentration of dissolved substances than cell

25. How does a change in salt concentration affect a cell?

26. Adding a Salt Solution to a Cell
Concentration of water is higher inside cell
Water flows out of cell High –> Low Concentration
Cell’s cytoplasm shrinks!!!

27. SALT shrinks!
Water rushes out!

30. Salt shrinks- water rushes out

32. Adding Distilled (Pure) Water to a Cell
Concentration of water is higher outside the cell
Water flows in the cell
Cell bursts/ruptures

33. Cell SWELLS!

34. Let’s Review…

36. Transport in Lower Organisms:
In ameba & paramecium
Transport by diffusion, osmosis & cyclosis

38. Intracellular Transport:
Transport inside the cell
Cyclosis- circular motion of the cytoplasm
Endoplasmic Reticulum
Diffusion, Osmosis, Phagocytosis & Pinocytosis

39. What process is being shown?

40. Transport in Plants: Vascular tissue- Roots- Xylem-transports water
Phloem- transports food
Roots-
Provide anchorage into soil
Absorb water

42. Capillary Action: Pulls water up into the xylem tubes
Adhesion- attraction between water molecules and the xylem tube
Cohesion- attraction between water molecules

43. Capillary Tube