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प्रश्न
Given alongside is the diagram of an experimental set-up:
Would you take any step before starting the experiment? Describe this step and explain its necessity.
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उत्तर
Before starting the experiment, it is necessary to destarch the leaves of the plant by keeping the plant in complete darkness for 48 hours. This is because if the plant is not destarched, then the experiment will give false results because starch stored previously may be detected in the leaf placed in the beaker even if no starch is produced during the experiment.
संबंधित प्रश्न
Describe fully one experiment with potted green plant to show that starch is not produced in the leaves when carbon dioxide is not available (diagrams essential)
Complete the following statement by choosing the correct alternative given below :
All animals would die on the earth if there was no ______.
The diagram is set up to demonstrate an experiment. Pond weed was placed in five water-filled tubes. The experiment was set up as shown in the diagram. The tubes were then left for 24 hours. Write the correct answer out of the five available choices:
(i) In which tube would you except to find the plant with the least amount of starch?
(a ) 1 (b) 2 (c) 3 (d) 4 (e ) 5
(ii) The tube in which most oxygen would be found is
(a ) 1 (b) 2 (c) 3 (d) 4 (e ) 5
(iii) The tube in which least carbon dioxide would be found is
(a ) 1 (b) 2 (c) 3 (d) 4 (e ) 5
(iv) The tube in which the plant would survive for the shortest length of time is
(a ) 1 (b) 2 (c) 3 (d) 4 (e) 5
Mention one difference between the following on the basis of what is given in bracket.
Chlorophyll and chloroplast (part of plant cell)
The chemical substance used to test the presence of starch in the cell of a leaf is ______.
Are the following statement true or false? Give a reason in support of your answer.
Destarching of the leaves of a potted plant can occur only at night.
A potted plant was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours. One of the leaves was covered with black paper in the centre. The potted plant was then placed in sunlight for a few hours.
During the starch test, why was the leaf
(1) boiled in water
(2) boiled in methylated spirit
Chloroplasts are called energy converters.
Given below is the diagram of an experimental set-up (final stage). Study the same and answer the following questions:
- What is the main aim of the experiment?
- Oxygen gas shown in the experiment is released from which of the raw materials?
- How would you confirm the presence of oxygen gas?
- Name the chemical substance which can be added in water to enhance the process/rate of release of oxygen gas.
- Draw a neat and labelled diagram of the same experiment for its initial stage.
