1. Structure and Function of the cell membrane

2. Structure and Function of the cell membrane
Contains lipids which allow the membrane to be fluid.

3. Structure and Function of the cell membrane
Contains lipids which allow the membrane to be fluid.
Acts as a barrier to the outside:

4. Structure and Function of the cell membrane
Contains lipids which allow the membrane to be fluid.
Acts as a barrier to the outside:
Selectively permeable

5. Structure and Function of the cell membrane
Contains lipids which allow the membrane to be fluid.
Acts as a barrier to the outside:
Selectively permeable- regulates what enters and leaves the cell

6. Structure and Function of the cell membrane
Contains lipids which allow the membrane to be fluid.
Acts as a barrier to the outside:
Selectively permeable- regulates what enters and leaves the cell
Also called a lipid bilayer

7. Membrane Structure
composed of large molecules of proteins and phospholipids.
Polar head (hydrophilic)
Non-Polar tails (hydrophobic)

8. Lipid bilayer

10. Parts of protein polar and parts nonpolar
Proteins are embedded in the membrane.
Parts of protein polar and parts nonpolar
Used for communication
Transportation

11. This is a fluid mosaic model of a cell membrane:
Why is it called this?

12. This is a fluid mosaic model of a cell membrane:
Why is it called this?
What is a mosaic?

13. Cell Walls

14. Cell Walls
Cell walls are found in plants, algae, fungi, and many prokaryotes.

15. Cell Walls
Cell walls are found in plants, algae, fungi, and many prokaryotes.
The cell wall lies outside the cell membrane.

16. Cell Walls
Cell walls are found in plants, algae, fungi, and many prokaryotes.
The cell wall lies outside the cell membrane.
Most cell walls are porous enough to allow water, oxygen, carbon dioxide, and certain other substances to pass through easily.

17. Cell Walls
Cell walls are found in plants, algae, fungi, and many prokaryotes.
The cell wall lies outside the cell membrane.
Most cell walls are porous enough to allow water, oxygen, carbon dioxide, and certain other substances to pass through easily.

18. Polar molecules are unable to enter the cell without help

19. How do materials move into and out of a cell?

20. How do materials move into and out of a cell?
To maintain homeostasis.

21. How do materials move into and out of a cell?
To maintain homeostasis.
All cells live in an aqueous environment
Substances that need to be moved are dissolved in liquid

22. How do materials move into and out of a cell?
Solution- mixture of substances

23. How do materials move into and out of a cell?
Solution- mixture of substances
Solute and Solvent

24. How do materials move into and out of a cell?
Solution- mixture of substances
Solute and Solvent
Concentration- amount of solute in a solvent

25. How do materials move into and out of a cell?
Passive transport:
does not need energy

26. 1. Diffusion If there is a gradient
Particles move from their highest concentration to the lowest concentration.

27. particles move until there is an equilibrium
1. Diffusion
If there is a gradient
Particles move from their highest concentration to the lowest concentration.
particles move until there is an equilibrium

28. Particles are evenly distributed
Equilibrium
Particles are evenly distributed

29. Low concentration
High concentration

30. Only some particles can freely move through the membrane.

32. Movement of water. Based on concentration gradients.
2. Osmosis
Movement of water.
Based on concentration gradients.

33. Based on concentration gradients
2. Osmosis
Movement of water.
Based on concentration gradients
which direction the water moves depends on the concentration of dissolved particles..

36. osmosis creates 3 situations
1. hypertonic solution
2. hypotonic solution
3. isotonic solution

37. Isotonic- Concentration of solutes
inside the cell is equal to outside the
cell.

38. Hypertonic- Concentration of solutes
is higher outside the cell.
Water leaves
Cell shrinks

39. Hypotonic- Concentration of solutes
is higher inside the cell.
Water enters
Cell expands and can burst

40. cell walls of plants and fungus prevent the cell from bursting.
some unicellular organisms have contractile vacuoles to get rid of extra water

41. Things that help with Diffusion
Proteins help the movement of large molecules across the membrane.

42. Things that help with Diffusion
Proteins help the movement of large molecules across the membrane.
Proteins form channels for the ions to pass

43. Things that help with Diffusion
Proteins help the movement of large molecules across the membrane.
Proteins form channels for the ions to pass
How fast they move depends on the concentration

44. Things that help with Diffusion
Proteins help the movement of large molecules across the membrane.
Proteins form channels for the ions to pass
How fast they move depends on the concentration
Does not require energy

45. 3. Facilitated Diffusion

46. Facilitated Diffusion
Step 1: when substrate attaches
protein changes shape.

47. Facilitated Diffusion
Step 1: when substrate attaches
protein changes shape.
Step 2: Now the substrate
can move.

48. Facilitated Diffusion
Step 1: when substrate attaches
protein changes shape.
Step 2: Now the substrate
can move.
Step 3: protein goes back
its original shape.

49. Active Transport Moves things against their concentration gradient.
Uses energy (ATP)
Uses carrier proteins and pumps

50. ATP
What is the structure of an ATP molecule?

51. ATP
What is the structure of an ATP molecule?
Sugar P

52. ATP What is the structure of an ATP molecule? Sugar P Nucleotide
Energy is contained between
the phosphate bonds.
When the bond breaks energy is
released.

53. Energy release
ATP- adenosine triphosphate -energy is being stored ADP- adenosine diphosphate -energy has been released

55. Sodium Potassium Pump
Protein will only open
if there is ATP

56. Sodium Potassium Pump Important for muscle contraction/ nervous system
Protein will only open
if there is ATP
Important for muscle contraction/ nervous system

57. Very large molecules move by vesicles
-proteins
-polysaccharides

58. Endocytosis
Membrane forms a pouch and moves materials into the cell.

61. Phagocytosis

62. Exocytosis

63. Cell Communication Cells need to sense the world around them.
Cells use hormones as signaling molecules.

64. Cell Communication Cells need to sense the world around them.
Cells use hormones as signaling molecules.
Receptor molecules- on the cell surface, able to bind to the messenger molecule.

65. Signal molecules can attach to the receptor on the protein to allow it to open.