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प्रश्न
Two healthy green plants were placed in the dark for 24 hours. They were then set up, as shown in the figure, for 4 hours. Then a leaf was taken from each plant and
the chlorophyll was removed from the leaves:
( i) What is the next and final step in this experiment?
( ii ) What would be the results of the final step?
( iii ) Why was it necessary to grease the glass sheet?
( iv ) What hypothesis is being tested in this experiment?

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उत्तर
(i) The leaf is then treated with iodine solution.
(ii) The leaf from first plant will not show starch test while the leaf from second plant will become blue-black showing the presence of starch.
(iii) It is necessary to grease the glass sheet to prevent the entry of air containing CO2.
(iv) The hypothesis that CO2 is necessary for photosynthesis is being tested in this experiment.
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संबंधित प्रश्न
Mention one difference between the following on the basis of what is given in bracket.
Chlorophyll and chloroplast (part of plant cell)
How would you demonstrate that green plants release oxygen when exposed to light?
Given below is the representation of a certain phenomenon in nature. With four organisms 1-4.

Name the biological process which was the starting point of the whole chain.
A potted plant was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours. One of the leaves was covered with black paper in the centre. The potted plant was then placed in sunlight for a few hours.
Draw a neat diagram of a chloroplast and label its parts.
Where are the chlorophyll pigments present in a cell?
ATP is needed for the dark reaction.
Choose the Odd One Out
Write the overall chemical equation for photosynthesis.
Name two plants having variegated leaves.
Match the terms given in column A with column B:
| Column A | Column B | ||
| (a) | Chlorophyll | (i) | Removes/absorbs CO2 |
| (b) | Methylated spirit | (ii) | Tests presence of starch |
| (c) | Potassium hydroxide | (iii) | Traps solar energy |
| (d) | Iodine solution | (iv) | Produces oxygen |
| (e) | Water | (v) | Bleaches chlorophyll |
