Get premium membership and access revision papers with marking schemes, video lessons and live classes.
Processing. Please wait.

 Form 1 Biology cell physiology questions and answers

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.

 (2m 16s)
545 Views     SHARE

Download as pdf file

Answer Text:
a)- The cell was placed in hypotonic solution compared to cell sap vacuole. Water molecules move into the cell by osmosis, causing the cell to distend as sap vacuole enlarges exerting turgor pressure which pushes the cytoplasm toward the rigid cellulose cell wall. Cells become turgid.
b)- When red blood cells are placed on a hypotonic solution, compared to cells cytoplasm, they gain water by osmosis, swell and eventually burst or haemolyse due to lack of rigid cellulose cell wall
c)- Distilled water will dilute the blood/ plasma becoming hypotonic compared to cytoplasm of blood cells. Cells therefore gain water by osmosis, swell and eventually haemolyse/burst due to lowering of osmotic pressure of blood below normal level