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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
the exact location of the Thylakoids
Fill in the blank:
Xanthophyll is ______ coloured pigment.
The production of starch, and not glucose, is often used as a measure of photosynthesis in leaves because
Are the following statement true or false? Give a reason in support of your answer.
Photosynthesis is considered as a process supporting all life on earth.
The figure below represents the vertical section of a leaf:
(i) Name the parts 1 to 5.
(ii) How many veins have been shown?
(iii) State the functions of parts 4 and 5.
Name the following:
The immediate product of photosynthesis.
Read the following sentences about photosynthesis:
- Sunlight, carbon dioxide, chlorophyll and water are necessary.
- Oxygen is absorbed.
- Leaves carry out photosynthesis.
- Proteins are made during photosynthesis.
Choose the correct pair of sentences that are true to photosynthesis.
Sunflowers open the petals in bright light during the daytime but close the petals in dark at night. This response of sunflowers is called ______.
Plants inhale and exhale continuously through the ______.
Draw the structure of the stomata and label the parts.
