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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
Cochlea, Malleus, Pinna, Stapes, Incus.
Complete the following paragraph by filling in the blank (1) to (5) with appropriate words:
To test a leaf for starch, the leaf is boiled in water to (1) _________. It is then boiled in Methylated spirit to (2) ________. The leaf is dipped in warm water to soften it. It is placed in a petri dish, and (3) _____ solution is added. The region of the leaf which contains starch, turns (4) ________and the region while does not contain starch, turns (5) __________.
The diagram given below represents an experiment to prove the importance of a factor in photosynthesis. Answer the questions that follow :
What will you observe in the experimental leaf after the starch test?
The following statement is about photosynthesis in a green plant. Write whether it is True or False.
The raw materials for photosynthesis include water and carbon dioxide.
Complete the following food chains by writing the names of appropriate organisms in the blanks:
______ → Mouse ______ → Peacock
Column ‘II’ is a list of items related to ideas in Column ‘I’. Match the term in Column ‘II’ with the suitable idea given in Column ‘I’.
| Column I | Column II | ||
| (i) | Grana | (a) | Decomposers |
| (ii) | Autotrophs | (b) | Light reaction |
| (iii) | By-products of photosynthesis | (c) | Animals |
| (iv) | Photolysis | (d) | Oxygen |
| (v) | Bacteria and fungi | (e) | Stimulated by light |
| (vi) | Chloroplast | (f) | Power |
| (vii) | Oxygen and water | (g) | Raw material |
| (viii) | Sunlight | (h) | Machinery |
| (ix) | CO2 and water | (i) | End products |
| (x) | Glucose (sugar) | (j) | Workrooms |
| (xi) | Cells in the leaf | (k) | By-products. |
Choose the correct option.
For fixation of 6 molecules of CO2 and formation of one molecule of glucose in Calvin cycle, requires
Gas exchange takes place in plants using _____.
The raw materials for photosynthesis are ______ and ______.
Name the minute openings seen on the lower surface of the leaf.
