In the experiment to show that sunlight is necessary for photosynthesis:
(a) What is done to destarch the green leaves of the potted plant initially?
(b) What is done to a part of destarched leaf so that photosynthesis may not take place in that part of the leaf (before keeping the potted plant in sunlight)?
(c) How is chlorophyll removed from the green leaf before further testing?
(d) Which reagent is used to test the presence/absence of starch in the parts of experimental leaf?

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Solution

(a) Initially, the plant is kept in dark for 24 hours to destarch the leafs.
(b) A part of destarched leaf is covered with black paper so that the light does not reach that region and photosynthesis does not occur.
(c) The chlorophyll is removed from the leaf green leaf before testing by boiling it in alcohol.
(d) The reagent used to test the presence of starch is called iodine.

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Similar questions

Q. A student is performing an experiment to show that sunlight is necessary for photosynthesis. In the first stage, he keeps a potted plant with green leaves in a dark place for about 3 days. Towards the end of the experiment, he boils one leaf in alcohol before using iodine for testing starch.
(a) Why is the plant kept in a dark place for about 3 days?
(b) Why is the leaf boiled in alcohol before testing for starch with iodine?

Q. A potted destarched plant was taken in order to prove that light is necessary for photosynthesis.
(i) What is meant by 'destarched plant'? How can it be destarched?
(ii) Using the destarched plant describe step by step how you would proceed to prove that in the absence of light the leaf cannot manufacture starch.

Q. A star-shaped figure was cut in the black paper strip used for covering a part of the leaf of a destarched plant used for demonstrating that light is necessary for photosynthesis. At the end of the experiment (after the removal of chlorophyll), the leaf was tested for starch with iodine solution.

(a) What colour, if any, will be produced on the part of leaf under the star-shaped figure?
(b) Give reason for your answer.

The procedure of an experiment is given as: Destarch the given potted plant. Cover a portion of leaf with a strip of black paper and keep it in sunlight for 6 hours. Test the presence of starch in the leaf.

What is the aim of the above experiment?

(i) Pluck the leaf to be experimented

(ii) Cover a portion of leaf on both sides by using strips of black paper

(iii) Keep the plant in dark place for three days to destarch its leaves.

(iv) Test the experimental leaf the the presence of starch

(v) Expose the plant to sunlight for four hours

(vi) Remove the black paper strip from the leaf

Given in the box are steps written randomly for the experiment to show that light is essential for photosynthesis. Which of the following sequences of steps is to be followed by the successful run of the experiment?

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