The given diagram shows a destarched, variegated leaf, partly covered by black paper. The plant is placed in bright light for several hours. |
Four discs are then cut from the leaf in the positions shown and are tested for starch. Which discs do/does not contain starch? |
A) 1, 3 and 4 only
B) 1 and 2 only
C) 2 only
D) 3 and 4 only
Correct Answer: A
Solution :
Only the disc 2 in the figure shows positive test for starch. This is because it contains chlorophyll and is receiving sunlight to synthesise food by photosynthesis. The discs 1 and 3 do not contain chlorophyll, thus, will not perform photosynthesis. Disc 4 is destarched and is covered by black paper. It contains chlorophyll but is not receiving sunlight to carry out the process of photosynthesis hence, cannot synthesise starch.You need to login to perform this action.
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