K.C.S.E Biology Q & A - MODEL 2017PP2QN03

K.C.S.E Biology Q & A - MODEL 2017PP2QN03

The diagram below illustrates the appearance of a plant cell after it had been put in a certain solution.

​(a) Explain the appearance of the cell at the end of the treatment. 
(b) Explain the results obtained if a red blood cell is subjected to the same treatment. 
(c) Explain why transfusion with distilled water is not recommended for a dehydrated patient.

answers

​(a) The cell is turgid; its cell sap was hypertonic (compared to the solution in which it was placed); by osmosis, water moved into the cell across its cell semi-permeable membrane, (swelling and becoming turgid);
(b)The red blood cell lacks the cell wall; water molecules move across its semi-permeable membrane by osmosis; into its hypertonic medium (inside the cell),cell contents/cytoplasm swelling and bursting haemolyses;
(c)Would haemolyse; due, to lowering of the osmotic pressure of the blood below normal;