Exercise 5 : Cell Transport E. Osmosis in Red Blood Cells Submitted by: Renz Algenio, Arianne Tan, Aloysius Bresnan, Joseph Chang, JR Castro
I. Abstract The study aims to find the effect of osmosis in cells. The researchers aim to answer as to how osmosis works and what are the different effects of different kinds of solutions to cells. In this exercise, the researchers used red blood cells and varying concentrations of NaCl solution, namely 0.07M, 0.15M and 0.30M. Three setups were made wherein each set up was exposed to a specific concentration of NaCl solution. All setups were observed for one hour and each setup produced different results. In this exercise it was found out that the manipulation of the concentration of solutions affects osmosis in red blood cells. II. Introduction As the basic unit of life, a cell has its own way to self-perpetuate. This may range from cell division, cellular respiration, up to the transport of different materials needed for these processes. One example of such process is osmosis that occurs inside of the cell. Osmosis is the net movement of a solvent, usually water, through a semi-permeable membrane. In this experiment, red blood cells were used to observe this process of osmosis. This is made possible by manipulating the concentration levels of the solution containing these RBCs. III. Methodology The researchers extracted blood from a volunteer. Three drops of blood should be extracted and be placed in glass slides. The glass slides should be labeled A, B and C and each glass slide should have one drop of blood. Then add a drop of NaCl solution for each slide. Add 0.07M to slide A, 0.15M to slide B and 0.30M to slide C. After tha addition of NaCl solutions, each set up would be observed for one hour at five minute intervals.
Pictures:
Fig 1 - Extracting of blood
Fig 2 – Placing of blood on a slide
Fig 3 – Observing of blood under a microscope IV. Results The table below shows the result of the relative size of each set up as per 20minute interval. This is compared to the initial appearance of the red blood cell.
Set-Up
After 20 mins
After 40 mins
After 1 hour
A B C
= = =
+ = -
++ = --
Legend: “+” - bigger as compared to initial “-“ - smaller as compared to initial “ = “ – equal as compared to initial
Pictures: Set-Up A:
Fig 4 – Set-Up A initial observation
Fig 5 – Set-Up A after 20 mins
Fig 6 – Set-Up A after 40 mins
Fig 7 – Set-Up A after 1 hour
Set-Up B
Fig 8 – Set-Up B initial observation
Fig 9 – Set-Up B after 20 mins
Fig 10 – Set-Up B after 40 mins
Fig 11 – Set-Up B after 55 mins to 1 hour
Set-Up C
Fig 12 – Set-Up C initial observation
Fig 13 – Set-Up C after 20 mins
Fig 14 – Set-Up C after 40 mins
Fig 15 – Set-Up C after 55 mins to 1 hour
V. Discussion For the first set-up, which is set-up A that was added with 0.07M, the cells tend to increase in size after some time. This result continues to be seen up to the last minute of observation. With this, it could be concluded that the cell in set-up A is in a hypotonic solution where in the water goes inside the cell because the amount of solute is higher there compared to the to outside the cell. This happens so that there would be equilibrium in the set-up. This explains the increase in size of the cell.
For the second set-up, which is set-up B that was added with 0.15M, the cells tend to remain the same as time goes by. This result continues to be seen up to the last minute of observation. With this result, we could conclude that the cell is exposed to an isotonic solution wherein the amount of solute is equal inside and outside the cell and the water goes in and out at the same rate. For the third set-up, which is set-up C that was added with 0.30M, the cells tend to shrink after some time and it is also seen that the red blood cells tend to move around. This result continues to be seen up to the last minute of observation. With this, we could conclude that the cell is exposed to a hypertonic solution wherein the amount or concentration of solute is greater outside the cell than inside the cell. This means that water moves outside the cell so that equilibrium would be maintained. This would explain the shrinking or shriveling of the cell.
