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प्रश्न
Enumerate the steps involved in testing a green leaf for the presence of starch.
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उत्तर
Test to determine the presence of starch in a leaf:
- Dip a leaf in boiling water for a minute to kill the cells.
- Boil the leaf in methylated spirit in a water bath to remove the chlorophyll, till the leaf turns pale blue and becomes hard and brittle.
- Now place the leaf in hot water to soften it.
- Place the leaf in a Petri dish and pour iodine solution over it.
- The appearance of a blue-black colour on the leaf is indicative of the presence of starch.
- The absence of starch is indicated by a brown colouration.
संबंधित प्रश्न
State the main function of the Lenticels
Put a tick (✓ ) against the most appropriate alternative in the following statement.
Which one of the following is an end-product of 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 .
(i) Fill in the blanks in the following equations of two chemical reactions:
(a) \[\ce{---+12H2O->[Light energy]C6H12O6 + --- + ----}\]
(b) \[\ce{--- 6O2->[Chlorophyll] 6 --- +6 ---- + Energy}\]
(ii) Name the two processes represented by the above two reactions.
(iii) State any two differences in these processes other than those already indicated in the reactions.
(iv) Which one of these two reactions is the supporter of all life on earth?
In the flowering plants, food is transported in the form of ______.
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.
The gas given out during photosynthesis is _____.
The reactions of photosynthesis make up a biochemical pathway.
What is the end product of light and dark reactions of photosynthesis?
______ food is made in their green stems.
Expand the abbreviation - NADP.
