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प्रश्न
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.
उत्तर
(i) The student is investigating the necessity of sunlight for photosynthesis.
(ii) The leaf portion which is not covered with black paper is the control as it receives sunlight.
(iii) The plant is kept in the dark before the experiment to destarch the leaves.
(iv) The leaf is tested for the presence of starch as follows:
-
- The leaf is boiled with alcohol over a water bath till it becomes colourless.
- It is rinsed with hot water to remove alcohol and spread it on a white tile.
- Pour iodine solution on it. The portion covered with black paper remains colourless while the rest of the leaf turns blue-black.
APPEARS IN
संबंधित प्रश्न
Put a tick (✓ ) against the most appropriate alternative in the following statement.
Stomata are present on the surface of:
Describe an experiment to prove that sunlight is necessary for photosynthesis.
(i) Fill in the blanks in the following equations of two chemical reactions:
(a) \[\ce{---+12H2O->[Light energy]C6H12O6 + --- + ----}\]
(b) \[\ce{--- 6O2->[Chlorophyll] 6 --- +6 ---- + Energy}\]
(ii) Name the two processes represented by the above two reactions.
(iii) State any two differences in these processes other than those already indicated in the reactions.
(iv) Which one of these two reactions is the supporter of all life on earth?
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.
On a bright sunny day, water weeds growing in an aquarium were actively giving off bubbles of gas. Use this information to answer questions that follow:
- Name the process occurring in the water weed that has resulted in the evolution of these bubbles.
- Of what gas do these bubbles consist?
- Briefly describe the reactions occurring in the leaves of the water weeds leading to the evolution of these bubbles.
- Give an overall balanced chemical equation to represent the process named in (i) above.
Using the destarched plant describe step by step how would you proceed to prove that in the absence of light the leaf cannot manufacture starch?
State whether true or false. If false, correct the statement.
Photosynthesis produces glucose and carbon dioxide.
State whether true or false. If false, correct the statement.
Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.
Write the reaction for photosynthesis?
______ food is made in their green stems.
