Red blood cell membranes are completely impermeable to sodium, potassium and chloride ions, however they are permeable to both water and urea. The concentration inside a red blood cell is 300mOsm and consists predominantly of sodium and potassium chloride.

a) With the aid of diagrams, decide what would happen to red blood cells when placed in the following solutions.

i. Fresh water.

ii. Salt solution at a concentration of 300mOsm.

iii. Salt solution at a concentration of 400mOsm.

iv. A urea solution at a concentration of 300mOsm.

b) Which solutions were isosmotic to the red blood cells?

c) Which solutions were isotonic to the red blood cells?