Question

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Date:
Long Answo-ouestons
01 Write an experiment to show sunlight is necessary for photosynthesis
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Answer 1

Answer:

Experiment to show that sunlight is necessary for photosynthesis - definition. Take a plant with destarched leaf. Leaf is partially covered with black paper on which a design is cut. Expose this plant to sunlight for few hours and perform a starch test with iodine solution.

Answer 2

Answer:

EXPERIMENT TO SHOW SUNLIGHT IS NECESSARY FOR PHOTOSYNTHESIS.

Explanation:

EXPERIMENT-

OBJECTIVE: To show that sunlight  is necessary for photosynthesis.

APPARATUS AND MATERIAL REQUIRED: A healthy potted plant, a petri dish, a beaker containing water,forceps,a water bath,a piece of wire gauze,a tripod,a burner, a box of matches,alcohol  a strip of black paper,iodine solution and clips.

THEORY: Photosynthesis is a biochemical process by which green plants  synthesis simple sugar in the presence of sunlight using carbon dioxide  from the atmosphere and water from the soil.This simple sugar[glucose] is later converted to starch.

6CO₂+12H₂O chlorophyll/sunlight C₆H₁₂O₆+6H₂O+6CO₂

The most important factor for photosynthesis is light. The rate of photosynthesis depends on the  quantity and quality of light. The chlorophyll molecule is green leaves absorbs light,get excited and emit electrons. The emitted electrons are used in the production  of ADENOSINE TRIPHOSPHATE.(ATP). Finally, the solar energy is converted into chemical energy and stored  in the glucose produced.

The rate of photosynthesis is the maximum in the presence of red light and blue light,while in green light the rate is minimum because green light is reflected by the chlorophyll molecules.

PROCEDURE:

1.Take the potted plant and keep it in the dark place for 2-3 days so that the leaves get destarched.

2.Cover a part of one of its leaves  with the strip of black paper. Make sure that you cover  both the sides of the leaves.

3. Now place this plant in sunlight for 3-4 hours.

4.Pluck the selected covered leaf and remove the black paper covering it.

5.Place this leaf in the beaker containing water and boil  it for about 10 minutes.

6. Take out the leaf  and now boil it in alcohol,using the water bath,for 10 minutes.This removes the chlorophyll.

7.Take out the leaf and wash it under running water.

8. Place this leaf in the Petri dish and put a few drops of iodine solution on it.Now  observe the change colour.

OBSERVATION: The leaf turns blue-black except in the covered region.As this covered region did not received light, photosynthesis did not occur. Hence no starch was formed there.The uncovered region received light and starch was formed  there due to photosynthesis.

RESULT: sunlight is essential for photosynthesis.

PRECAUTIONS:

1.Before starting the experiment, the leaf must be distracted.

2.The leaf must be  covered with black paper properly to prevent the entry of light.

3. Boiling the leaf in alcohol should be done in the water bath.