The permeability of the cell membrane

1, experimental purpose

II, Small Molecule Cross-Membrane Transport Overview

Unlike artificial lipid double-layer membranes, biofilms allow not only water and non-polar molecules to pass through through with simple physical diffusion, but also polar molecules such as ions, sugars, < a href" > amino acids, < a href and > many cell metabolites pass through specific mechanisms.

If red blood cells are placed in various solutions, depending on the permeability of the red cytocyte membrane to various solutes, some solutes can penetrate, some solutes can not penetrate. Even if it can penetrate, the speed varies. The rate of infiltration can be recorded by observing the different times of red blood cell hemolysis. The phenomenon of hemoglobin escaping from red blood cells is called hemolysis. The solute seeping into red blood cells can increase the permeation pressure of red blood cells, causing water to enter red blood cells, causing hemolysis and cell membrane rupture. At this point, light is easier to pass through the solution, so that the solution transparent is hemolysis. The time of hemolysis is different because of the different speed at which the solute penetrates. Therefore, differences in the permeability of various substances can be measured by hemolysis.

III, material, >" and instrument

4, experiment

2． Hemolytic phenomenon observation: taketest tube one added 3mL distilled water, added 1 drop or 2 drops of diluted chicken blood, light mix, and then static attention to observe the color changes of the solution. Due to the rupture of red blood cells, the color of the solution is gradually brightened by the turbid red color. This is a hemolysis phenomenon.

3． Osmotic time comparison of chicken red blood cells:

1) for three different concentrations of NaCl (5mmol/L NaCl, 65mmol/L NaCl, 0.15mol/L NaCl) when hemolytic, note that from the drip of red blood cells, the operation method is the same 2. Pay attention to observe color changes, answer whether there is hemolytic phenomenon? Why?

5, Results and Analysis