Osmotic Properties of Cells
...2 degrees Celsius is 0.54%. The solution equilibrated at 4 degrees Celsius has its highest percent hemolysis at 0.2% salinity where the pellet was observed to be white in color (Figure 1.) The white color of the pellet indicates that most of the cells did not hemolyze at 0.2% salinity and 4 degrees Celsius. The solutions percent hemolysis then slopes down to 0% at 0.75% salinity, where the pellet was observed to be a red color (Figure 1). The red colored pellet indicates that most of the cells did not hemolyze and still contain their hemoglobin while in the pellet at 0.65% salinity and 4 degrees Celsius. The solution equilibrated at 4 degrees Celsius remains at 0% hemolysis from 0.75% to 0.9% salinity (Figure 1.) The calculated hemolysis 50 for the solution equilibrated at 4 degrees Celsius is 0.62%. In order to study the effects of propranolol on cell membrane fragility, tests were used to see how many cells hemolyzed at high, low, and zero concentrations of propranolol at 22 degrees Celsius, which is about room temperature. The percent hemolysis of blood cells for the saline solutions containing different concentrations of propranolol varies greatly. The saline solutions containing high concentrations of propranolol (600 ug/ml) at 22 degrees Celsius, has a high percent hemolysis from 0% salinity to 0.65% salinity (Figure 2.) The pellet was observed to be a white color from 0% to 0.65% salinity. The white color of the pellet indicates that most of the cells did not hemolyze between 0% and 0.65% salinity. The percent hemolysis of this solution then drops sharply to 0% at 0.9% salinity where the pellet was observed to be a red color (Figure 2.) The red colored pellet indicates that at 0.9% salinity most of the cells did not hemolyze and remained intact in the pellet. The calculated LD 50 for the saline solution containing high concentrations of propranolol is 0.59%. The saline solution containing low concentrations of propranolol (10 ug/ml) at 22 degrees Celsius, has the highest percent hemolysis of blood cells at 0.2% salinity where the pellet was observed to be a white color (Figure 2.) The white color of the pellet represents the color of only the cell membranes left after most of the cells hemolyzed at 0.2% salinity and low concentrations of propranolol. The percent of hemolysis of this solution then slopes downward until reaching almost 0% at 0.75% salinity (Figure 2.) The saline solution containing low concentrations of propranolol remains at 0% hemolysis from about 0.75% to 0.9% salinity (Figure 2.) A red colored pellet was observed from 0.60% to 0.9% salinity. The hemolysis 50 for the saline solution containing low concentrations of propranolol is 0.48% The saline solution controls lacking propranolol at 22 degrees Celsius in Figure 2 is identical to the saline solution at 22 degrees Celsius in Figure 1. The highest percent hemolysis for this solution occurs at 0.2% salinity where the pellet is observed to be the color white indicating that the pellet is made primarily of membranes of hemolyzed cells (Figure 2.) This solution then has a gradual curve down to a low 0.6% salinity where the pellet was observed as being a red color indicating that the whole cells containing their hemoglobin were in the pellet. The percent hemolysis for the solution equilibrated at 22 degrees Celsius remains low until finally reaching 0% at 0.9% salinity. The calculated LD 50 for the solutions equilibrated at 22 degrees Celsius is 0.54%. Discussion: The results show that blood cells in all three temperatures media, hemolyze completely at 0% salinity. This is due to osmosis in which the high concentration of saline solution outside the cell rushing into the low concentration of water inside the cell causing the cell to swell and burst. Greater than 90% of the blood cells hemolyzed in solutions equal to or below 0.4% salinity in all three temperature media. This implies that 0.4% salinity is still to high and the membrane can not be held together. The prediction for this experiment is that the propranolol will reinforce the cell membrane making it stronger. Also the lower the temperature the lower the flexibility of the cell membrane is. Seeing how about 50% of the blood cells hemolyzed at a near freezing temperature, suggests that the cell membrane must be weaker at colder temperatures. This supports the hypothesis that a cold environment causes the cell membrane to become brittle or not flexible. A red blood cell’s shape, a biconcave disc, can expand and accommodate a certain volume of water entering the cell. However, at colder temperatures, such as 4 degrees Celsius, the membrane becomes brittle and less flexible. This inflexibility does not allow for much movement of the cell membrane, and consequently does not allow for much water to enter the cell before hemolysis takes place. This also supports the prediction that a lower temperature would have a higher LD 50 than a higher temperature medium. With the temperature medium being at 22 degrees Celsius, the blood cells did not go through hemolysis until the concentration of water outside the cell was considerably greater than the concentration of water inside the cell. This suggests that the cell membrane was able to stretch with the added volume of water flowing into the cell. A temperature of 22 degrees Celsius allows the membrane of the cell to have a bit more flexibility than 4 degrees Celsius. At warmer temperatures the cell membrane becomes more flexible and able to accommodate a larger volume of water without going through hemolysis. This also supports the hypothesis that the lower the temperature medium the lower the flexibility of the cell membrane is. The concentration of water was higher on the outside and allowed for a vast difference in water concentration compared to inside the cell. Since water flows from a high concentration to a low concentration, the cell will get flooded with water while trying to obtain equilibrium. Since only 50% of the blood cells hemolyze at 0.44% salinity at 37 degrees Celsius, this suggests that the cell membrane has an even greater capacity to stretch and accommodate the greater volume of water inside the cell. A warmer temperature of 37 degrees Celsius makes the cell membrane become more fluid and able to stretch so that the cell will not hemolyze at varying concentrations. Upon compiling all of the above-mentioned data, the hypothesis that a cell membrane will become less flexible when at lower temperatures is supported. At some point in the separation process hemoglobin molecules escape across the cell membrane into the external water. This well known hemolysis phenomenon will be in...