Cell Permeability Essay Research Paper Cell membrane

Cell Permeability Essay, Research Paper

Cell membrane permeability refer to the crossing of the cell membrane by substances. Substances move into or out of the cell by crossing the cell membrane. Some substances cross the membrane very easily and the membrane is said to be very permeable to these substances; others move across with difficulty, while others are excluded completely. There are various process that a substance may used to cross the cell membrane, such as diffusion, facilitalated diffision, or a substance may inter a cell by a mean of a cell membrane carrier, which requires some kind of energy, such as ATP. In any of the process that a substance may used to cross the cell membrane it has to be determined by the gradient of that particular substance that is crossing, that is the charge that the gradient has or the concentration of that particular substance making its way into the cell by passing the cell membrane. Other important aspect of cell membrane permeability is the rate of the substance to cross the cell membrane, which depends on what kind of cell it is or what is the substance that is trying to cross the membrane.

This experiment is divided into three parts as follow: (A) Hemolysis of Erythrocytes, (B) Hemolysis and phylogenetic relationships, and (C) Permeability of cell membrane in relation to fat solubility. Part A, Hemolysis of Erythocytes, the concentration of each solute that will produce hemolysis on red blood cells. The concentration is measure by using different solute such as sucrose, sodium sulfate, and calcium chloride. Each of the measurements had been measure in units of osmolar since it is the measure of effective solute concentration and is dependent on the number of active particles and not on the kind of particles Part (B) is hemolysis and phylogenetic relationships is to measure the times of hemolysis, the rapture of the cell capsule, for the rat blood. The different solutes that were used to measure the time of hemolysis are urea, ethylene glycol, thiourea, and glycerol. Depending of the molecular weight of the solute, that is going to be the amount of time that it would take for the red blood cells to reach hemolysis, there are other factors that are involved in determining the time of hemolysis, these are going to be known when the results for the experiment stated on the results section of the report. Also, in these part of the experiment comparison between human, rat, and mouse red blood cells are going to make. Part (C) is permeability of cell membrane in relation to fat solubility, many fat compounds enter the cell membrane depending on the fat solubility that the substance contain. One of the main aspects that has a lot to do on the solubility of the substance to enter the cell membrane mostly depends on the partition coefficient that the cell membrane enclose. The substances that are being used in this part of the experiement to test the lipid or fat solubility are being tested are alcohols such as, methyl alcohol, ethyl alcohol, and propyl alcohol.

Methods

Part A ? Hemolysis of Erythrocytes

- Rat blood is going to be used throughtout the experiment.

- Add 5 drops of rat blood to the suspension that was prepare from solute and water (see handout p. 4).

- Inversed test tube and check for hemolysis within 30 seconds (handout p. 4).

Part B ? Hemolysis and phylogenetic relationships

- Add 5 drops of rat blood to 2ml of each of the solutions being used

(see handout p. 5).

- The following solutions are being used for this section: Urea, Ethylene Glycol, Thiourea, and Glycerol.

Part C ? Permeability of cell membrane in relation to fat solubility

- Add five drops of rat blood to 2ml of isosmotic solution and note time of hemolysis as before (see handout p. 5).

- Solutions being used: methyl alcohol, ethyl alcohol, and propyl alcohol.

Results

Part A ? Hemolysis of Erythrocytes

In this part of the experiment it is determinated the concentration of each of the the solutions being used which just produces hemolysis.

Solution Concentration (mOsm) Contribution per mM

NaCl 95 1.86

Sucrose 89 1.0

Na2SO4 99 2.9

CaCl2 104 2.6

For this section of the experiment one have to understand that the osmotic pressure of the red blood cells is 300 mOsm, and from the concentration that we acquired during the experiment we conclude that rat blood cells will go into hemolysis since their osmotic pressure this different and a equilibrium can not be obtain. From the data above one can determinate that sucrose has the lower concentration since it molarity is low compared to the others, and its membrane permeability is low compared to the others solutions such as NaCl and Na2SO4. CaCl2 on the other hand, has the higher concentration and the highest molarity of all the solution, it?s molarity is about 0.08 ?0.10, and its membrane permeability would need more concentration of it to pemetrate the cell membrane. Each of the solution also has its own contribution per mM to its concentration, this it more like a reference for to it?s molarity of each solution.

Part B ? Hemolysis and phylogenetic relationships

The times to hemolysis for rat blood, human blood, and mouse blood.

Solute Human Rat Mouse

urea (60.1) 7 (secs) 5

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