1. It is a jungle: The Cell Membrane

2. Cell membrane
This is the surface boundary of the cell. It separates the cell's internal parts from the extra cellular materials and environment. It defines the cell.
Also called the Plasma membrane or cytoplasmic membrane it forms the surface boundary of the cell.

3. Same structure as Organelle formation
Internal cell membranes form the membrane bound organelles: endoplasmic reticulum, Golgi apparatus, lysosomes and nucleus.

4. Functions: maintain cell's integrity
allow identification of cell‑ owner, species
id is by certain protein molecules on the surface of the plasma membrane that are unique to the cells of one individual.
communication ‑ compounds from other cells (hormones, neurotransmitters) bind to receptors on the surface of specific protein membranes (binding sites) thereby initiating changes in the cell's activity.

5. transportation ‑ some but not all substances move or are moved through the membranes by various mechanism.
defense ‑ some proteins (antibodies) on the surface of
lymphocytes bind to harmful substances (antigens) thereby initiating a series of events to denature the antigens.

6. The STRUCTURE: Close up

7. The membrane structure
consists primarily of phospholipids, proteins and cholesterol.
The current model of the membrane is called the fluid mosaic model.

9. Phospholipids: foundation of cell membrane
Hydrophilic: polar, water loving head made of phospholipid.
Hydrophobic: nonpolar, water fearing tails made of 2 fatty acid chains

10. Cholesterol makes the membrane more stable.
Temperature sensitive: less fluid at moderate temperatures, but slightly more liquid than it normally would be at cold temperatures
helps maintain its functionality and strength over a wide range of temperatures.

11. Cell Membrane Structure

12. Fluid Mosaic Model
a fluid lipid bilayer with a mosaic pattern of protein molecules embedded in and through the layers. The lipid hydrophilic phosphate heads point outward; while the hyrophobic fatty acid tails point inward, towards each other.The plasma membrane is selectively permeable. Restricting the passage in and out of the cell.

13. Selection is based on : size of molecules if lipid soluble
charge of ions
presence of carrier molecules
Movement of substances through cell membranes.

14. Types of processes to cross over
physical
physiological

15. 2 energy paths
Passive transport is driven by the kinetic energy of the molecules being transported or by membrane transporters by facilitate crossing.
Active transport depends upon the expenditure of cellular energy in the form of ATP hydrolysis.

16. Physical :
processes in which random, never ceasing movements of molecules and ions supply energy for moving substances.

17. Physiology use of proteins, pores, pumps and channels
Concentration gradients- facilitated diffusion
Osmosis- e.g. blood

18. Types Passive Active Transport
Diffusion: ‑ osmosis
‑ (simple) filtration
Active Transport
- endocytosis ( phagocytosis, pinoctosis)
- exocytosis
- facilitated diffusion

20. Passive Transport
Diffusion ‑ movement of ions or molecules from an area of higher concentration to area of lower concentration, so as to create a balance mixture
Osmosis ‑ movement of solvent particles across the membrane into a region in which there is a higher concentration of solute particles.

21. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. The movement is due to collisions, which occur more frequently in areas of higher concentration

22. osmosis

24. Movement across membrane
BBC diffusion/osmosis

26. Net osmosis ‑ more water moves in one direction through membrane than in opposite direction. net osmosis occurs down water concentration gradient. tends to equilibrate two solutions separated by selectively permeable membrane.
Osmotic pressure is pressure that develops in solution as result of net osmosis into it.
Filtration ‑ the process by which fluid passes through a membrane due to a difference in pressure on the two sides.

27. Filtration
movement of solvent (water in body) and solutes through membrane in one direction only. down the hydrostatic pressure gradient.
Diffusion occurs in both directions through the membrane, filtration only one direction.
Net filtration ‑ of solute occurs down solute concentration gradient.

28. Facilitated diffusion

29. Active Transport Active processes : require energy
Active Transport ‑ involves the movement of materials across the cell membrane against a concentration or electrical gradient and requires a source of energy, ATP.
Physiological: or active transport; energy (ATP) is used to move substances across membrane. energy source chemical reactions in cells.
types ‑ active transport mechanisms

30. Endocytosis Endo- into Phagocytosis: cell eating
Pinoctosis: cell drinking

31. Exocytosis
Exo- out

33. Other ways in
Channels
Pores
Proteins which act as carriers
pumps

34. Channels and Carriers

35. Animations of types of transport

36. Solutions Water + solids dispersed or disassociated in the water.
Classified as
-Isotonic
Hypertonic
Hypotonic
In reference to salt concentrations

37. Isotonic solution ‑ physiological norm
Isotonic solution ‑ physiological norm. .9% NaCl potential osmotic pressure the same as solution compared with.
Hypertonic solution ‑ greater osmotic pressure. high solute low water concentration
Hypotonic solution ‑ lower osmotic pressure. lower solute high water concentration

38. Water and salt relationship
In general, water moves toward the area with a higher solute concentration because it has a lower water concentration

39. "ISO" means the same
If the concentration of solute (salt) is equal on both sides of the cell membrane, the water will move back in forth but it won't have any result on the overall amount of water on either side.

40. "HYPO" means less
In this case there are less solute (salt) molecules inside the cell. Water's concentration is greater outside the cell, so water will move into the cell.

41. Hypotonic
The cell will gain water and grow larger. In plant cells, the central vacuoles will fill and the plant becomes stiff and rigid, the cell wall keeps the plant from bursting
In animal cells, the cell may be in danger of bursting, organelles called CONTRACTILE VACUOLES will pump water out of the cell to prevent this.

42. “HYPER" means more
In this case there are more solute (salt) molecules outside the cell. Water's concentration is greater inside the cell so will move out (toward the lower concentration).

44. Hypertonic
In plant cells, the central vacuole loses water and the cells shrink, causing wilting.
In animal cells, the cells also shrink.
In both cases, the cell may die.

45. In the Blood Effects

47. Points to take with you
Remember that all material that the cell gets from the environment or sends to the environment has to go through the cell or plasma membrane. The membrane is basically a phospholipid bi-layer with various proteins embedded into it. What's key to realize is that the cell membrane is semi permeable, that is some materials can get through the membrane while others can't.

48. Cell allows things need to enter
Chemicals that can pass through the membrane
Chemicals that cannot pass through the membrane
gases
Water
Small polar molecules- wastes
Lipids
Anything lipid soluable
Ions, Na, Cl, H, K
Large molecules
e.g. proteins, sugars
Amino acids

49. animations Animation of fluid mosaic model
Animation of transport across membrane
a good one
Active transport BBC

50. Movement through membrane

51. Membranes Go to page: http://content. cdlib. org/xtf/view
Image url:

52. Opening picture tutorial at telstar. ote. cmu
Opening picture tutorial at telstar.ote.cmu.edu/Hughes/tutorial/cellmembranes