Higher Biology Homework Help?

Question

(a) With reference to the contents of a red blood cell and very concentrated salt solution, explain the meaning of the terms hypotonic and hypertonic solution.

(b) Describe the effect of a hypertonic solution of sugar on red onion cells.

Answer 1

a)  A red blood cell placed in a hypotonic solution (e.g., pure water) bursts immediately ("hemolysis") from the influx of water.  If red cells are placed in sea water (about 3% salt), they lose water by osmosis and the cells shrivel up. Sea water is hypertonic to their cytosol.

b)  Water will leave the onion cells by osmosis resulting in the contents of the cell coming away from the cell wall in a process called plasmolysis. The cells are said to be plasmolysed.