An Experiment Based on Phtosynthesis

Introduction:

Photosynthesis is the use of sunlight to produce carbohydrates. In order to produce carbohydrates, photosynthesis converts the energy in sunlight to chemical energy in sugar bonds. Photosynthesis takes place in only the green parts of plants, which the green part are chlorophyll pigments. An example of this would be the leaves of a plant. In order for photosynthesis to occur sunlight, carbon dioxide, and water are essential, however oxygen is produced in the process. Photosynthesis consists of two connected sets of reactions. The first reaction is triggered by light which produces oxygen from water. The second produces sugar from carbon dioxide, this is known as the Calvin Cycle. Both reactions are connected by electrons that are released when water is spilt to form oxygen.

Photosynthesis occurs in the chloroplasts of leaves. The chloroplast consists of photosynthetic pigments chlorophyll A, chlorophyll B, carotene, xanthophyll, and enzymes. The chloroplast captures light energy and is built into the membranes of thylakoids, which also store other pigments. The reaction of photosynthesis is

6〖CO〗_2+6H_2 O+Light energy -〉 C_6 H_12 0_(6 )+6O_2

The products of the photosynthesis reaction are ATP and NADPH, which the Calvin Cycle then uses these products. ATP provides energy for the cycle while NADPH provides electron to reduce carbon dioxide in order to form carbohydrates.

The first part of the experiment was to test for the presence of starch in plant leaves. A portion of a leaf was covered in foil; therefore no light absorption occurred into the chloroplasts in this portion. The hypothesis for this experiment was that the covered part of the leaf did not contain starch, but the uncovered, or exposed, ar...

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...t distances is because the molecules vary in size, therefore they differ when placed in a non-polar hydrophobic solvent. The different pigments absorb different wavelengths of light at different rates. The carotene, orange, moved the farthest up making it hydrophobic. Chlorophyll-A, dark green, was the next farthest making it more hydrophobic than chlorophyll-B, light green. The xanthophyll, yellow bands, were the least hydrophobic and moved the least. This proved the hypothesis was not supported. The polar aldehyde function group on the chlorophyll-B makes it less hydrophobic than chlorophyll-A. Meanwhile the extra polar group on the xanthophyll makes them less hydrophobic than the carotene. This importance of this experiment was to show that the different color pigments in the leaver are made up of different structures and absorb light at different wavelengths.