EXPERIMENT – 9 To Prove that Light is Necessary for Photosynthesis. Aim : To show experimentally that light is necessary for photosynthesis. Requirements : A potted plant‚ iodine solution‚ black paper strip‚ paper clips‚ water bath. EXPERIMENT PLEASE VIEW THE ANIMATION FILE FOR THE PROCEDURE Observation : 1) The region of the leaf which was exposed to sunlight turns blue in colour. 2) The region of the leaf covered with black strip turns brownish in colour
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bacteria. The purpose of crystal violet in the Gram’s stain procedure is to differentiate bacteria into two different groups of pink and purple colours with gram positive being purple and gram negative being pink in colour. D. What is the purpose of iodine in the Gram’s stain procedure? What is a mordant? Keeps
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the UN’s Standing Committee on Nutrition World Nutrition Situation 5th report‚ stunting‚ which is the prevention of growing or developing properly‚ affects more than 147 million preschoolers in developing countries. The same report also shows that Iodine deficiency accounts for the world’s utmost single cause of mental retardation and brain damage. The World Food Program reports that undernutrition affects school performance and studies have shown it often leads to a lower income as an adult. The
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SO4-2(aq) + H2O(l) Balance the reaction. Which substance is the oxidizing agent? What is the equivalent weight of H2O2 (Molar mass = 34.0 grams) in the above reaction? What is the normality of a 0.040 M H2O2 solution used in the above reaction? 8) Iodine reacts with thiosulphate ion (S2O3-2) in acidic solution to form iodide and tetrathionate ion (S4O6-2). Calculate the volume in mL of 0.100 M Na2S2O3 needed to react with 0.2538 g of I2. (Answer = 20.00 mL) 9) Thyroxine (C15H11I4NO4) is a hormone
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their Gram classifications. Materials Broth cultures of Staphylococcus aureus and Pseudomonas fluorescenes‚ a Bunsen burner‚ one inoculating loop‚ one clean glass slide‚ one slide dish‚ bibulous paper‚ Gram-staining materials (Crystal Violet‚ Iodine‚ Ethyl Alcohol‚ Safranin‚ DI water)‚ and a microscope. Methods Smear Preparation Obtained a clean dry glass slide‚ Staphylococcus aureus and Pseudomonas cultures. Added drop of water onto the center of slide. 3. Flame-sterilized inoculating
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drops of Lugol’s iodine solution were added to each of the test tubes. The test tubes were mixed thoroughly. Test tube 1 was placed under a flame for observation. Colour change within the test tubes were recorded. Protein test 10 test tubes were used and lab-elled. 9 of the test tubes were filled with 5ml of food sample. 3 drops of Biuret reagent were added to each of the test tubes. The test tubes were gently shaken to mix the solution. Observation of colour change was
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together). As the reaction progresses‚ less starch will be present and more sugar (maltose) will be present. In lab‚ the activity of amylase was observed by using iodine. Remember‚ iodine reacts with starch to form a dark brown/purple color. As amylase breaks down starch‚ less and less starch will be present and the color of the solution (if iodine is added) will become lighter and lighter Rates of enzyme-catalysed reactions depend on pH and temperature. The optimum temperature is about 40oC because the
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tests performed were iodine testing for starch‚ Benedict’s test for glucose‚ the grease spot test for lipids‚ and the CuSO4’s test for protein. The pH indicator’s detection is based upon observing a chemical change that takes place most often a change in color. The Starch test was used for the presence of starch. In this instance‚ the distilled water is a negative control for the test‚ and a known glucose solution is a positive control. This was a simple test in which iodine is added to a given
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sugar in it by adding Benedict’s solution and heating it‚ there would be a color change if a reducing sugar is present‚ or it will remain blue (no reducing sugar). The objective of the Starch test was to test for starch in substances by using Iodine. The iodine will cause a substance to turn to a dark blue color if it is positive for starch. The objective for the Dye test was to test for lipids. When mixed with water and the tested substance‚ a positive result will occur in it being separated from
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temperature. * Temperature influences time taken for iodine solution remains yellowish. No full marks will be given if students did not meet the 2 criteria of answer and the word ‘different’ / ‘influence’ is not specific. Students must try to avoid these words. Accurate response (3 marks): P1: Temperature of water bath P2: Time taken for iodine solution to remain yellowish (Horizontal observation) * At temperature 5˚C‚ time taken for iodine solution remains yellowish is 12 minutes. * At
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