definition of photosynthesis

Photosynthesis, the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.

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Mohl's half leaf experiment

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Experiment to demonstrate Moll’s half-leaf experiment for showing that CO 2 , light, chlorophyll and water are necessary requirements for photosynthesis: Requirements: A potted plant, caustic potash, wide- mouthed bottle, iodine, split cork, water Method: 1. De-starch a potted plant by putting it in complete darkness for two days. 2. Fill partly a wide-mouthed bottle with strong solution of caustic potash and fit a split cork on its mouth. 3. Insert about half of the portion of a leaf of the de-starched plant into the bottle through the split cork (Fig. 36). 4. Place the whole apparatus in light after applying grease on the upper portion of split cork, and test the leaf for stach after about 10 hours. Observations: Portions of the leaf inside the bottle as well as in between the split cork show negative test for starch indicating the absence of photosynthesis while the portions outside the split cork show positive test for starch indicating the presence of process of photosynthesis in
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EUTROPHICATION

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When water bodies such as lakes, estuaries and slow moving streams receive excess nutrients ,it results in excessive plant (algal) growth . This process is called eutrophication. This excessive growth of plants such as  Water hyacinth and algae reduces the dissolved oxygen (BOD- biological oxygen demand) in water. The water body then becomes incapable of supporting fishes and  other forms of aquatic life. Excessive growth of algae in such water bodies is described as algal bloom. Nitrates and phosphates are the two main substances(nutrients) that causes such condition, which is a direct result of pollution. These nutrients come from a variety of sources,such as fertilizers applied to agricultural fields and golf courses, excessive use if detergents, erosion of soil containing nutrients,untreated sewage and discharges from sewage treatment plants. EUTROPHICATION not only leads to reduced oxygen but also produce foul odour and slow death of water body. Thus, biodiversity in t
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Hydrilla plant experiment

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Experiment to demonstrate that oxygen is evolved during the process of photosynthesis: Answer Requirements: Beaker, water, test tube, funnel, Hydrilla plant. Method: 1. Fill the beaker with the water and take an aquatic plant, such as Hydrilla, in the beaker. 2. Cut the bases of the plants, tie them with a thread and cover them with an inverted funnel in such a fashion that the cut ends of plants are towards the neck of the funnel.  3. Fill a test tube with the water and invert it on the upper end of the funnel. 4. Keep the whole apparatus in sunlight and observe for some time. Observations: From the cut ends of the plant some bubbles are coming out continuously and they are collected at the top of the test tube by displacing the water.  Test for the gas: To test the gas released, bring a burning match stick near the mouth of the test tube which would burst into flames. This shows that the gas released is oxygen.  Results: The liberated gas is oxygen and it is evolved due to the photol
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