Abstract on Determining the Photosynthetic Activity in Plants Using Different Wavelengths of Light using Chromatography and a Spectrophotometer
In this experiment, the separation of particular pigments, contained within a fresh spinach leaf, were examined. Paper chromatography is the process of separating certain molecules, or pigment molecules, based upon their polarity. Four different pigments were examined from the spinach leaf: chlorophyll a, chlorophyll b, xanthophyll, and carotene. Based upon looking at the pigments individual molecule structures, our group hypothesized that the most polar molecule, chlorophyll b, would travel the shortest amount up the chromatography paper, and the least polar pigment, carotene, would travel the furthest up the chromatography paper. The results showed that the most polar molecule within each pigment traveled the least far up the chromatography paper, which is also polarized. The least polar pigment traveled the farthest up the paper since it was more attracted to the non polar solvent ( acetone) and polarized chromatography paper.
In addition, the results of the separation of pigments yielded from the chromatography paper was then cut in separate pieces and placed into cuvettes. These cuvettes contained samples of each pigment and were examined with a spectrophotometer to obtain the absorbance spectrum for each pigment’s wavelength. Pigments are substances that absorb light and convert it into chemical energy. Pigments absorb some wavelengths and reflect others. The color of light that we see is composed of wavelengths that the object did not absorb. Each pigment has a characteristic absorption spectrum, which shows which wavelengths of visible light it absorbs the best. Our prediction for this part of the experiment was that if chlorophyll a absorbs blue-violet light, chlorophyll b absorbs blue light, carotene absorbs blue-green light, and xanthophyll absorbs blue light, then the wavelengths of greatest...
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