University of Santo Tomas Faculty of Pharmacy 1AMT Group 2 Members: Kristiana Calupitan, Koleen Chavez, Valerie Co Carlson David, Eleonor Dolorfino, Princess Estimo Exercise 9: Starch as Indirect Evidence of Photosynthesis I. Introduction Glucose, the immediate sugar produced in photosynthesis is used by the plant in respiration. The excess of it, however, is polymerized and stored as starch in amyloplasts. To produce both carbohydrates products, the plant has an absolute need for light as energy source and the photosynthetic pigments chlorophyll. II. Objectives 1. To determine the presence of starch as an indirect end-product of photosynthesis 2. To determine the necessity of light and chlorophyll pigments in photosynthetic process 3. To determine the relationship between the rate of photosynthesis and the detection of starch in plant organs III. Materials Dark and light Mayana leaves Beaker Petri dish Water Ethanol Iodine solution IV. Methodology/ Procedure V. Results and Explanation Fresh Specimen (Column A) Boiling Water (Column B) Boiling Alcohol (Column C) Iodine Solution (Column D) “D ark Leaf” Col or of Water: Yellow C olor of Alcohol: Green Color of Leaf: Brown “L ight Leaf” Col or of Water: Yellow Co lor of Alcohol: Green Color of Leaf: Blue-black One indication of photosynthetic activity in plants is the detection of starch in plant organs. The presence of starch may be detected in actively photosynthesizing green parts of the leaves. Xanthophyll was extracted from the leaves in Column A making the water yellow in color. In Column B, the chlorophyll from the leaves was extracted making the boiling alcohol green in color. The presence of starch was determined through the iodine solution. It has produced more starch in the “light leaf” since it is exposed in light and light is a valuable component of photosynthesis. VI. Conclusion Sunlight supplies the energy for