InterviewSolution
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InterviewSolution
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23,dw a labeled diagram or stomata24 Give an ex5ahimo the process of asexual reproduction in hydra with diae an experiment to show presence of starch in leaves |
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Answer» Testing a leaf for starch is the simplest photosynthesis lab.A positive test for starch in a leaf provides evidence thatphotosynthesishas occurred. The test for starch is a leaf is an is an extension of theIodine Test for Starch. Glucose is the product of photosynthesis, and is rapidly converted to granules of starch - a polymer of glucose - for storage. Starch granules have been visualized in the stroma of the chloroplast as well as the cytoplasm. The test for starch in a leaf is also a part of the otherphotosynthesis experiments. So, take time to understand the test for starch in a leaf. APPARATUS/MATERIALS REQUIRED:-bunsen burner, tripod stand, wire gauze(OR 90oC electric water bath OR hot plate) 250 cm3 beaker boiling tube anti- bumping granules forceps test tube holder white tile leaf to be tested (hibiscus leaves are excellent) 90% ethanol iodine/potassium iodide solution Procedure Remove a green leaf from a plant that has been exposed to sunlight for a few hours Half-fill a 250cm3 beaker with water. Heat the water until it boils. Keep the water at boiling point. Use the forceps to place the leaf in the boiling water. Boil for 2 minutes. Turn off the Bunsen Burner. (If you are using a heat source without a naked flame - electric water bath or hot plate - this step is unnecessary.) Place the boiled leaf in a boiling tube containing 90% ethanol. Place the boiling tube in hot water and boil for 10 minutes or until the leaf decolourizes. ( It may be necessary to replace the ethanol) Gently remove the leaf and wash with a fine trickle of cold tap water. Spread the leaf evenly on a white tile. Add a few drops of iodine/potassium iodide solution to the leaf and note any observations. Observations/Results The leaf was flaccid (soft) after being boiled in water The ethanol changed from colorless to green The leaf was brittle after being boiled in ethanol The leaf become flaccid once more after being rinsed in cold water After iodine solution was added... Observation No color change (Iodine Solution remains brown) Iodine/Potassium Iodide solution changed from brown to blue- black Interpretation Starch is not present Starch is present |
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