K.C.S.E Biology Q & A - MODEL 2011PP2QN01
The set-up below illustrates a procedure that was carried out in the laboratory with a leaf plucked from a green plant that had been growing in sunlight.
(i) What was the purpose of the above procedure?
(ii) Give reasons for carrying out steps A, B and C in this procedure.
(iii) Name the reagent that was used at the step labelled D.
(iv) State the expected result on the leaf after adding the reagent named in (iii) above.
(i) - Testing a leaf for the presence of starch;
(ii) - A - kill the leaf/break down cells/stop enzymatic activity;
B - Removal of chlorophyll;
C - Soften leaf/makes leaf less brittle;
(iii) Iodine solution;
(iv) Areas where starch is present stain blue/blue black;