K.C.S.E Biology Q & A - MODEL 2012PP1QN04

K.C.S.E Biology Q & A - MODEL 2012PP1QN04

In an investigation, a student extracted three pieces of paw paw cylinders using a cork borer.
The cylinders were cut back to 50 mm length and placed in a beaker containing a solution.
The results after 40 minutes were as shown in the table below.

​(a) Account for the results in the table above. 
(b) What would be a suitable control set-up for the investigation? 

answers

​(a) The solution was hypotonic/less concentrated compared to the cell sap of pawpaw cylinder cells;
The tissue/cells gained water by osmosis; becoming turgid/longer/stiff;
(b) Pawpaw cylinders of the same size/length; placed in an isotonic solution;
Boiled potato cylinders of the same size; placed in a similar solution;