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प्रश्न
A candidate studied the importance of certain factors in photosynthesis. He took a potted plant and kept in the dark for over 24 hours. In the early hours of the next morning, he covered one of the leaves with black paper in the centre only. Then he placed the plant in sunlight for a few hours and tested the leaf which was covered with black paper for starch.
Describe step by step, how the candidate proceeded to test the leaf for the presence of starch?
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उत्तर
- The student dipped the leaf in boiling water for a minute to kill the cells.
- Then he boiled the leaf in alcohol/methylated spirit over a water bath to remove chlorophyll. The leaf becomes hard and brittle.
- He then places the leaf in hot water to soften it.
- Next the student spreads the leaf in a dish and pours iodine solution on it. The presence of starch is indicated by a blue-black colour.
- The uncovered portion (exposed to sunlight) turned blue-black colour and the covered portion showed brown colour. The difference in the colours of covered and uncovered part of leaves indicates the importance of sunlight in photosynthesis.
संबंधित प्रश्न
Formalin, Iodine, DDT, Lime
How does carbon dioxide return to the atmosphere? Explain.
A student in order to study the importance of certain factors of photosynthesis took a potted plant and kept it in the dark for over 24 hours. Then in the early hours of the morning the student covered one of the leaves with black paper in the centre only. Student placed the potted plant in the sunlight for a few hours, and then tested the leaf which was covered with black paper for starch.
(i) What aspect of photosynthesis was being investigated?
(ii) Is there any control in this experiment? If so, state the name.
(iii) Why was the plant kept in the dark before the experiment?
(iv) Describe step by step how the candidate proceeded to test the leaf for the presence of starch.
The diagram alongside represents an experiment conducted to prove the importance of a factor in photosynthesis.
Study the same and then answer the questions that follow:
(i) Name the factor being studied in his experiment.
(ii) Why was the plant kept in a dark room before conducting the experiment?
(iii}Why was the experimental leaf then kept in
1. boiling water 2. methylated spirit?
(iv) Name the solution used to test for the presence of starch in the leaf.
(v) What will we observe in the experimental leaf at the end of the starch test?
(vi) Give a balanced chemical equation to represent the process of photosynthesis.
Complete the following food chain by writing the names of appropriate organisms in the blanks:
__________ → Mouse → _________ → Peaock
Explain the term Plastoquinone.
Give technical term:
In photosynthesis radiant energy is converted into which from?
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Land plants obtain their CO2 from the atmosphere.
Choose the correct option.
For fixation of 6 molecules of CO2 and formation of one molecule of glucose in Calvin cycle, requires
What will happen if we remove plants from the aquarium?
State whether true or false. If false, correct the statement.
Plants lose water when the stomata on leaves are closed.
