Investigating the osmotic fragility of erythrocytes and investigating the components making up human blood

Extract

[...] The experiment was carried out with the aim of "investigating the effect of salt concentration on the integrity of red blood cells in sheep's blood". Sheep's blood was mixed with 11 solutions of different concentrations of water and sodium chloride, they were then centrifuged and then their absorbance was read using a spectrophotometer. A research hypotheses can be made, since erythrocytes have salt present in them, as we add blood to solutions with lower concentrations of sodium chloride they will start to lyse as more water will enter the red blood cells since the RBCs will be hypertonic and the solution outside will be hypotonic. [...]

[...] This test can also be used to detect hereditary spherocytosis which causes problems with the membrane of the RBCs, this can also lead to anemia5. If I were to carry out this experiment again, I would repeat the experiment 3-5 times to get an average which would be more accurate and more reliable compared to the result recorded after doing the experiment once. Also if the test tubes weren't clear after centrifugation, they should be centrifuged further until a clear solution is obtained. [...]

[...] The readings from the spectrophotometer were recorded in a table. Results: Table (Volume of NaCl and deionised water added to each test tube labelled 0-10, and the absorbance measured using the spectrophotometer.) Tube Number 1 2 3 4 5 6 7 8 9 10 Volume Of NaCl 1 2 3 4 5 6 7 8 9 10 Volume Of Deionised Water 10 9 8 7 6 5 4 3 2 1 Absorbance 0.888 0.609 0.522 0.630 0.735 0.614 0.730 0.469 0.439 0.135 0.012 Sample Calculation: Tube 10 = 10g NaCl Hence the concentration of test tube 10 is 170.9 millimoles/l, using this method we can calculate the concentration for the other test tubes. [...]

[...] Once the NaCl was added deionised water was added to the tubes using a 10ml Gilson Pipette. Tube 0 had no NaCl added to it, it had only 10cc of water. Water was added in decreasing volumes of 1cc from tube tube 1 had 9cc of water, tube 2 had 8cc of water added and so on. Tube 10 had no water added to it and had 10cc of NaCl in it. After all the solutions were made the total volume of each test tube was 10cc. [...]

[...] Sheep's Blood Used as the source for erythrocytes. 50?l Gilson Pipette Used to add blood to the solutions due to its accuracy. 10ml Gilson Pipette Used to add water and NaCl accurately to form the 11 solutions. 11 test tubes were labelled 0-10 using a marker and placed in a test tube stand. Using a 10ml Gilson Pipette NaCl was added to the tubes in increasing volume of 1cc. Tube 1 had 1cc of NaCl, tube 2 had 2cc of NaCl and so on. [...]