In an experiment to investigate a factor affecting photosynthesis, a potted plant which had been kept in the dark overnight was treated as shown in the diagram below and exposed to light.
(a) Why was the potted plant kept in the dark overnight?
(b) Which factor was being investigated in the experiment?
Answer:
a)
To de-starch the leaves
b)
Carbon (IV) oxide concentration.
c)i)Test for starch
ii)P-Iodine solution retains its yellow-brown colour.
Q-Iodine solution turns blue-black/black.
iii)
P-Carbon (IV) oxide required for photosynthesis was absorbed by NaOH.
Photosynthesis did not take place hence starch was not formed.
Q-The leaf had all requirements for photosynthesis hence starch was formed
iv)
-Comparison purpose or act as control.
To de-starch the leaves
b)
Carbon (IV) oxide concentration.
c)i)Test for starch
ii)P-Iodine solution retains its yellow-brown colour.
Q-Iodine solution turns blue-black/black.
iii)
P-Carbon (IV) oxide required for photosynthesis was absorbed by NaOH.
Photosynthesis did not take place hence starch was not formed.
Q-The leaf had all requirements for photosynthesis hence starch was formed
iv)
-Comparison purpose or act as control.
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