Cell Membrane and Permeability
Cell Membrane Permeability and Osmosis
Experiment 3
Objectives:
To demonstrate the mechanism involved in Osmosis;
To demonstrate the tonicity of solutions by subjecting the cells to different concentration of solute.
To view, under the microscope, any change in the shape and volume of the cells after subjecting them to different concentrations of solutes;
To demonstrate the permeability of cell membrane by subjecting the cells to different solutes;
To demonstrate the mechanism involved in Gibbs-Donnan Equilibrium.
Cell Membrane
A flexible outer surface that separates the internal from outer region.
Semi permeable membrane – selective barrier
Structure of the Cell Membrane – “Fluid Mosaic Model”
Fluid Mosaic Model
Ever moving sea of fluid lipids that contains biomolecules carbohydrates and proteins
Lipid Bilayers -phospholipids -cholesterol -glycolipids
Osmosis
The passage of water from a region of lower solute concentration through a semi-permeable membrane to a region of high solute concentration.
There are two separate experiment we have done (Hemolysis and Osmotic pressure) to demonstrate the mechanism involved in Osmosis.
Hemolysis from the Greek αἷμα (aima, haema, hemo-) meaning "blood" and λύσις (lusis, lysis, -lysis) meaning a "loosing", "setting free" or "releasing" is the rupturing of erythrocytes (red blood cells) and the release of their contents (hemoglobin) into surrounding fluid (e.g., blood plasma).
5 drops of distilled water can activate hemolysis on a 0.2 ml of whole blood. After centrifuging the blood it causes separation of the red blood cell (sediment) and the plasma (supernatant).
The hemolyzed sample is transparent, because there are no cells to scatter light.
Hemolysis (Experiment)
Osmotic Pressure
The osmotic pressure of a solution depends upon the number of particles dissolved regardless of the size. Therefore, more concentrated solutions will have greater osmotic pressure than dilute ones.
Experiment 3
Objectives:
To demonstrate the mechanism involved in Osmosis;
To demonstrate the tonicity of solutions by subjecting the cells to different concentration of solute.
To view, under the microscope, any change in the shape and volume of the cells after subjecting them to different concentrations of solutes;
To demonstrate the permeability of cell membrane by subjecting the cells to different solutes;
To demonstrate the mechanism involved in Gibbs-Donnan Equilibrium.
Cell Membrane
A flexible outer surface that separates the internal from outer region.
Semi permeable membrane – selective barrier
Structure of the Cell Membrane – “Fluid Mosaic Model”
Fluid Mosaic Model
Ever moving sea of fluid lipids that contains biomolecules carbohydrates and proteins
Lipid Bilayers -phospholipids -cholesterol -glycolipids
Osmosis
The passage of water from a region of lower solute concentration through a semi-permeable membrane to a region of high solute concentration.
There are two separate experiment we have done (Hemolysis and Osmotic pressure) to demonstrate the mechanism involved in Osmosis.
Hemolysis from the Greek αἷμα (aima, haema, hemo-) meaning "blood" and λύσις (lusis, lysis, -lysis) meaning a "loosing", "setting free" or "releasing" is the rupturing of erythrocytes (red blood cells) and the release of their contents (hemoglobin) into surrounding fluid (e.g., blood plasma).
5 drops of distilled water can activate hemolysis on a 0.2 ml of whole blood. After centrifuging the blood it causes separation of the red blood cell (sediment) and the plasma (supernatant).
The hemolyzed sample is transparent, because there are no cells to scatter light.
Hemolysis (Experiment)
Osmotic Pressure
The osmotic pressure of a solution depends upon the number of particles dissolved regardless of the size. Therefore, more concentrated solutions will have greater osmotic pressure than dilute ones.