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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
Mention one difference between the following on the basis of what is given in bracket.
Producers and consumers (mode of nutrition)
Mention one difference between the following on the basis of what is given in bracket.
Grass and grasshopper (mode of nutrition)
Name the membrane that connects thylakoid of one granum With the other granum.
Complete the following food chain by writing the names of appropriate organisms in the blank:
Grass → __________ → Lion
Name the following:
Source of oxygen given out in photosynthesis.
Complete the following sentence with appropriate word:
One of the products of ______of water is oxygen.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
KOH absorbs CO2.
Choose the Correct Answer:
A plant is kept in a dark cupboard for about 48 hours before conducting any experiment on photosynthesis to:
Plants inhale and exhale continuously through the ______.
A potted plant with variegated leafes was kept in dark for 24 hours and then placed in bright sunlight. Answer the following questions.
- Which aspect of photosynthesis is being tested in the above diagram?
- Why was the plant kept in the dark for 24 hours?
- After the starch test, what will be the colour of the yellow and green parts of the leaf? Give reasons to support your answer.
