2. Al-Hujraat Surah: 49 Aya: 11

4. REQUIREMENTS FOR LIVING
All living things have certain requirements , which they must satisfy in order to remain alive;
Maintain homeostasis
These include exchanging gases (O2 and CO2),
Taking in water, minerals, Vitamins and food,
Eliminating wastes.
These tasks happen at the cellular level.
Molecules move through the cell membrane by Osmosis and inside the cell by diffusion.

5. OSMOSIS and DIFFUSION

6. Introduction
Since the early days of civilization mankind have adopted simple forms of membranes.
In early agriculture communities, household sieves were invented and developed to separate fine grain from coarse grain particles and shells.
Similarly, cheese cloth was made from cotton fibers and used to manufacture cheese.

7. Introduction
All forms of separation are based on differences in particle size.
However, developments in membrane technology have focused on adoption of other separation mechanisms, such as differences in solution and diffusion rates of various species across the membrane material.

8. Membrane based Separation
A number of membrane-based desalination processes are used on industrial scale.
the membrane-based processes include
Reverse osmosis,
Nanofiltration,
Ultrafiltration, and
Microfiltration.

9. Differences among membranes
Microfiltration operates on a particle size range of 0.10 µm to 0.15 µm.
Ultrafiltration operates on a particle size range of 0.15 µm to 5xl0-2 µm
Nanofiltration operates on a particle size range of 5xl0-2 µm to 5x10-3 µm
Reverse osmosis operates on a particle size range of 5xl0-3 µm to 10-4 µm.

10. Molecules are always moving
Molecules move randomly and bump into each other and other barriers

11. Concentration gradient
Concentration Gradient - change in the concentration of a substance from one area to another.

12. Diffusion
Molecules in solution tend to slowly spread apart over time. This is diffusion.

13. Diffusion
Movement of molecules from an area of high concentration to an area of lower concentration.
Factors that affect the rate of diffusion: size of molecules, size of inter molecular space , temperature, pressure, and concentration.

14. Diffusion [High] [Low] diffuse, low energy molecules
concentrated, high energy molecules
[High]
[Low]
diffuse, low energy molecules

15. Diffusion will continue until equilibrium is reached
Diffusion will continue until equilibrium is reached. This means there will be an equal distribution of molecules throughout the space. This is why food coloring moves throughout a beaker of water; why odors smell strong at first and then disappear over time.
Equilibrium, a result of diffusion, shows the uniform distribution of molecules of different substances over time as indicated in the above diagram.

16. How is this Important ?
Diffusion is an important concept for humans because our very existence depends on it.
The cells of the human body utilize diffusion every day!
Can you think of where in the human body diffusion might be important?
An important place in the human body where diffusion occurs is the lungs. Oxygen diffuses from inside the lungs to the circulatory system.

17. OSMOSIS
Osmosis is the flow of solvent through a semi- permeable membrane such as cell membrane, from a dilute solution to concentrated solution.
Osmosis is a selective process.

18. Osmosis
Osmosis is the movement of WATER across a semi-permeable membrane
At first the concentration of solute is very high on the left.
But over time, the water moves across the semi-permeable membrane and dilutes the particles.

21. Osmosis
Osmosis is a special case of diffusion commonly found in biological systems (In your cells).
Water transport and turgor pressure in the cell is maintained by osmosis.

22. Turgor Pressure Turgor: pressure against the cell membrane
Hypotonic: there is an excess of water and the cell bursts.
Hypertonic: there is not enough water and the cells shrivels.
Osmosis regulates these occurrences.

23. Osmosis
Eventually the pressure difference between the arms stops osmosis.

24. Force per unit area that prevents water from passing through membrane
Osmotic Pressure
Force per unit area that prevents water from passing through membrane

25. Osmotic Pressure
The hydrostatic pressure at equilibrium which prevents the passage of more solvent through the semi permeable membrane is called osmotic pressure.

26. P
If applied pressure is too low, H2O flows into the region of higher solute concentration...
“Down the concentration gradient” for H2O. P
Membrane
Pure H2O
H2O +
Solutes

27. P
If applied pressure is too high, H2O flows into the region of lower solute concentration...
Against the natural concentration gradient for H2O.
--Reverse Osmosis P
Membrane
Pure H2O
H2O +
Solutes

28. P
Minimum pressure required to maintain equal flow rates (to prevent infusion of H2O).
Proportional to solute concentration differences across membrane. P
Membrane
Pure H2O
H2O +
Solutes

29. Units of Osmotic Pressure
OSMOLE
Non electrolyte:
1 M Solution = 1 osmole = 22.4 atmospheres
= 22.4 x 760 mm Hg
= mm Hg.
Electrolyte:
Dissociates into ions
Bimolecular double osmotic pressure….NaCl
Tri molecular tripple osmotic pressure…..CaCl2

30. Osmotic Pressure
Osmotic pressure, , is the pressure required to stop osmosis:
Π = osmotic pressure M = Molarity (mol/L)
R = Ideal Gas Constant T = Temperature (K)

31. Problem #2 Calculate osmotic pressure for 0.10 M Na3PO4 at 20°C.
Na3PO4 ionizes into 4 particles,
(3 Na + 1 PO4),
Ion conc. is = 0.40 M
p = MRT = (0.40) (0.0821) (293) = 9.6 atm

32. Problem #1: Calculate molarity if soln. in water (300K) has osm
Problem #1: Calculate molarity if soln. in water (300K) has osm. pressure of 3.00 atm
M = p / RT
(3.00 atm)
[ atm.L / mol) (300K)]
= 0.122M

33. Osmosis – A Special kind of Diffusion
Diffusion of water across a selectively permeable membrane (a barrier that allows some substances to pass but not others). The cell membrane is such a barrier.
Small molecules pass through – ex: water
Large molecules can’t pass through – ex: proteins and complex carbohydrates

34. Hypotonic – The solution on one side of a membrane where the solute concentration is less than on the other side. Hypotonic Solutions contain a low concentration of solute relative to another solution.
Hypertonic – The solution on one side of a membrane where the solute concentration is greater than on the other side. Hypertonic Solutions contain a high concentration of solute relative to another solution.

35. Over time molecules will move across the membrane until the concentration of solutes is equal on both sides. This type of solution is called ISOTONIC.

36. Cytoplasm is a solution of water and solids
(solutes dissolved in the water).
Water moves into and out of cells because of the different concentrations of the solutes.
Different kinds of cells react differently depending on the solution they are in.
Below are examples of red blood cells in different types of solutions and shows what happened to the red blood cells.

37. PLANT CELLS Hypotonic Solution Hypertonic Solution
Turgor Pressure builds in the cell and causes osmosis to stop
because of the rigid cell wall.
Plants will wilt when cells
lose water through osmosis.

38. PASSIVE TRANSPORT
Passive transport occurs without expenditure of energy. Molecules move using their own kinetic energy . Diffusion and osmosis are examples of passive transport. Passive transport allows cells to get water, oxygen and other small molecules that they need. It also allows the cell to get rid of waste such as carbon dioxide.
DIFFUSION
OSMOSIS

39. Reverse Osmosis Water Purification

40. Home water purification by reverse osmosis

41. Kidney and Dialysis

42. Artificial kidney

43. A Dialysis Unit

44. Principle of Dialysis

45. Transmembrane Diffusion
Arterial End
“Head pressure” --High
Venous End
“Head pressure” --Low
Tissue Cell
Wastes
Head pressure of heart “pushes” nutrients and water into cell (PBLOOD> POSMOTIC).
Nutrients
Hypertonic blood “draws” wastes into blood (POSMOTIC>PBLOOD) .

46. THANKS