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प्रश्न
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.
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उत्तर
(i) Destarched plant is the plant which lacks starch. Destarching is done by keeping the plant in dark for 2-3 days or covering a part of a leaf with a black paper by clip.
(ii) (a) The leaf is plucked and is boiled in water and decolourized with alcohol.
(b) The portion of leaf which received light turns blue with iodine because photosynthesis took place in that part of leaf.
(c) The part of leaf which was covered with black paper remains colourless because photosynthesis could not take place in the absence of sunlight.
This shows that starch is not manufactured in the absence of light.
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संबंधित प्रश्न
Phosphate, RNA, Sugar, Nitrogenous base
Put a tick (✓ ) against the most appropriate alternative in the following statement.
Carbohydrates are stored by plants in the form of:
Put a tick (✓ ) against the most appropriate alternative in the following statement.
Stomata are present on the surface of:
Short answer question.
What is the source of energy for photosynthesis?
Given below is the overall chemical equation of photosynthesis which is incomplete in certain respects.
\[\ce{CO2 + H2O ->[Chlorophyll] C6H12O6 + H2O + O2} \]
Rewrite the equation in its complete form .
In the flowering plants, food is transported in the form of ______.
What is meant by a destarched plant? How can it be destarched?
A healthy croton plant bearing variegated leaves was kept in a dark cupboard to destarch it after which it was placed in sunlight for a few hours. One of the leaves was then plucked and an outline of the leaf marking the green and the non-green regions was drawn. The leaf was then tested for starch. Using the above information, answer the following questions:
- State the aim of the above experiment.
- Name the chemical used for testing the presence of starch.
- Why is the leaf boiled in water and alcohol before testing for the presence of starch?
- What change is seen on the leaf after the starch test?
- Give the chemical equation to represent the process of starch formation in plants.
Write the reaction for photosynthesis?
How does the light-dependent reaction differ from the light-independent reaction? What are the end product and reactants in each? Where does each reaction occur within the chloroplast?
