E6 - Investigation of the Photochemistry of Chlorophyll The aim of this experiment is to investigate the photochemistry of chlorophyll. This experiment will be performed in two lab periods. In the first lab period you will extract chlorophyll, the green pigment in leaves, from spinach. In the second lab period you will investigate the interaction of light with chlorophyll. Read in Appendix B the reference section titled "Electronic Structure of Matter" copied from reference 1 before performing experiment investigating the photochemistry of chlorophyll.
Chlorophyll is the green pigment responsible for the color of leaves. Its presence in leaves is crucial for photosynthesis. Photosynthesis can be defined as the process by which plants, algae, and photosynthetic bacteria use light energy to drive the synthesis of organic compounds. The photosynthetic process involves the removal of CO2from the atmosphere, which is used to synthesize carbohydrates, and results in the release of O2. The energy to drive the chemical reactions of photosynthesis comes from the sunlight absorbed by the chlorophyll molecules. Hence, the first step in photosynthesis is the absorption of visible light from the sun by chlorophyll molecules. The chlorophyll molecules then transfer the light energy to chloroplasts, the reaction center of photosynthesis. In this way light energy is converted to chemical energy for converting CO2 into carbohydrates. The overall reaction for photosynthesis is:
This overall equation for photosynthesis is deceptively simple. In fact, a series of complex reactions must occur in a coordinated manner for the synthesis of carbohydrates. To produce a sucrose molecule, C6H12O6, plants require about 30 distinct proteins that work within a complicated membrane structure.
Without light photosynthesis cannot take place; and hence the absorption of light by chlorophyll is the first step in photosynthesis