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प्रश्न
Given below is the figure of an experimental set-up, showing a physiological act of the plants. Study and answer the following questions:
- What is the objective of this experiment?
- Name and define the process shown here.
- Why do we destarch the leaves before performing the experiment?
- How do we destarch the leaves?
- What will be the observation when we pour iodine solution over the bleached experimental leaf?
- Write a well-balanced equation for the above process.
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उत्तर
- To demonstrate the need for sunlight for photosynthesis.
- Photosynthesis. Photosynthesis is the process by which plants produce glucose using water, carbon dioxide, sunshine, and chlorophyll pigment in their leaves. Photosynthesis produces glucose and oxygen as its end products. Plants use glucose to power their cells, while other species require oxygen for respiration.
- We remove starch from a plant to facilitate photosynthesis in the presence of sunlight. If starch is already present in the leaves, photosynthesis does not take place.
- By keeping the leaves in a dark room for 24 to 48 hours, we can destarch them. This is because darkness inhibits photosynthesis and enables the plant to use up any stored starch.
- If starch is present, the bleached experimental leaf will turn blue-black when iodine solution is applied. The leaf is said to be starch-free if there is no colour change and it stays brown.
- \[\ce{6CO2 + 6H2O ->[Sunlight][Chlorophyll] C6H12O6 + 6O2}\]
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)
The diagram alongside refers to an experiment in which the apparatus was set up with the light source 10 cm away from the plant. After 15 minutes the number of bubbles evolved per minute from the cut stem was recorded. The light source was moved to 20 cm away from the plant, left for 15 minutes and the number of bubbles evolved per minute was again recorded. The experiment was repeated with the light source at distances of 40, 60, 80 and 100 cm away from the plant. Plot a graph for the results obtained and answer the following questions.
(i) From the graph it seems likely that the rate of bubbling per minute at 50 cm would have been
(a) 2.0 (b) 2.5 (c) 3.0 (d) 3.5
(ii) The gas produced by the plant during the experiment was
(a) air (b) oxygen (c) carbon dioxide (d) nitrogen (e) hydrogen
(iii) The gas collected comes due to the breakdown of
(a) glucose (b) starch (c) water (d) air (e) ATP
(iv) If ice cubes were added to the water, the rate of bubble formation would
(a) Stay the same.
(b) Increase because more water is added.
(c) Decrease because the temperature drops.
(d) Decrease because water freezes.
(e) Cannot tell from the information given.
(v) If some sodium bicarbonate is added to the water the rate of bubble formation
(a) Increases because more respiration occurs.
(b) Increases because more photosynthesis occurs.
(c) Increases because the gas becomes less soluble.
(d) Decreases because carbon dioxide acts as a limiting factor.
(e) Decreases because respiration decreases.
Name the following:
The source of carbon dioxide for aquatic plants.
Complete the following by filling the blanks 1 to 5 with appropriate words/terms/phrases:
To test the leaf for starch, the leaf is boiled in water to ______ (1). It is next boiled in methylated spirit to ______ (2). The leaf is placed in warm water to soften it. It is then placed in a dish and ______ (3) solution is added. The region which contains starch, turns ______ (4) and the region which does not contain starch, turns ______ (5)
Given below is a schematic diagram to illustrate some aspects of photosynthesis.
- Fill up the gaps, in blank spaces (1-4), by writing the names of the correct items.
- What phenomenon do the thick arrows A and B indicate?
Given below is the representation of a certain phenomenon in nature. With four organisms 1-4.
Name any one organism that could be shown at No .5
Given below is the representation of a certain phenomenon in nature. With four organisms 1-4.
Name the biological process which was the starting point of the whole chain.
Chlorophyll is necessary for photosynthesis.
Name the following:
The green colouring matter of the plants.
Name the following:
The site of light reaction in the cell of a leaf.
