Question
In an experiment to investigate a factor affecting photosynthesis, a leaf of a potted plant which had been kept in the dark overnight was covered with aluminium foil as shown in the diagram below.
The set up was kept in sunlight for three hours after which a food test was carried out on the leaf.
(a) Which food test was carried out?
(b) (i) State the results of the food test.
(ii) Account for the result of the food test.
(c) (i) Why was the set up kept in sunlight for three hours.
(ii) Why was it necessary to keep the plant in the darkness before the experiment?
The set up was kept in sunlight for three hours after which a food test was carried out on the leaf.
(a) Which food test was carried out?
(b) (i) State the results of the food test.
(ii) Account for the result of the food test.
(c) (i) Why was the set up kept in sunlight for three hours.
(ii) Why was it necessary to keep the plant in the darkness before the experiment?
Answer
(a) Starch
(b) (i) The covered part remained brown ;uncovered part turned blue-black
(ii) - Starch formed in uncovered part of the leaf (because of light)
- Starch not formed in Covered part of the leaf (because of lack of light)
(c) (i) To allow photosynthesis /manufacture of food
(ii) To destarch the leaf /remove starch from the leaf
(b) (i) The covered part remained brown ;uncovered part turned blue-black
(ii) - Starch formed in uncovered part of the leaf (because of light)
- Starch not formed in Covered part of the leaf (because of lack of light)
(c) (i) To allow photosynthesis /manufacture of food
(ii) To destarch the leaf /remove starch from the leaf
Related Topics