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प्रश्न
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.
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उत्तर
(i) Destarched plant is the plant which lacks starch. Destarching is done by keeping the plant in dark for 2-3 days or covering a part of a leaf with a black paper by clip.
(ii) (a) The leaf is plucked and is boiled in water and decolourized with alcohol.
(b) The portion of leaf which received light turns blue with iodine because photosynthesis took place in that part of leaf.
(c) The part of leaf which was covered with black paper remains colourless because photosynthesis could not take place in the absence of sunlight.
This shows that starch is not manufactured in the absence of light.
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संबंधित प्रश्न
Put a tick (✓ ) against the most appropriate alternative in the following statement.
Which one of the following is an end-product of photosynthesis?
Given below is the overall chemical equation of photosynthesis which is incomplete in certain respects.
\[\ce{CO2 + H2O ->[Chlorophyll] C6H12O6 + H2O + O2} \]
Rewrite the equation in its complete form .
Describe an experiment to prove that sunlight is necessary for photosynthesis.
What is meant by a destarched plant? How can it be destarched?
A candidate in order to study the importance of certain factors in photosynthesis took a potted plant and kept it in the dark for over 24 hours. Then in the early hours of the morning, she covered one of the leaves with black paper in the center only. She placed the potted plant in the sunlight for a few hours, and then tested the leaf which was covered with black paper for starch.
- What aspect of photosynthesis was being investigated?
- Is there any control in this experiment? If so, state the same.
- Why was the plant kept in the dark before the experiment?
- Describe step by step how the candidate proceeded to test the leaf for the presence of starch.
The reactions of photosynthesis make up a biochemical pathway.
Explain how the biochemical pathway of photosynthesis recycles many of its own reactions and identify the recycled reactants.
______ food is made in their green stems.
Can the stem of a plant be compared with a street with two-way traffic? Give reason.
Name two raw materials for photosynthesis.
Write the exact location of palisade cells.
