Submitted by: Submitted by

Views: 1164

Words: 416

Pages: 2

Category: Other Topics

Date Submitted: 08/25/2010 12:42 PM

Report This Essay


The purpose of this lab was to analyze the photosynthetic pigments present in plants and to investigate the rate of photosynthesis. In Part A of the experiment, we conducted tests that extracted each pigment that played a vital role in the light absorption process within the spinach leaf. By using chromatography we managed to extract 4 different accessory pigments, Carotene, Xanthophyll, Chlorophyll a and Chlorophyll b were the pigments present. This data contradicted my hypothesis of being 5 different accessory pigments rather than 4. Each accessory pigment is present in order to absorb the wavelengths that are not accepted by chlorophyll. The accessory pigments absorb these secondary wavelengths and transfers the energy to be used as the same sort of energy that produced by chlorophyll. The Part B of the lab, we used colorimeters to measure the percent transmittance through the various cuvettes used and the chlorplast solutions in each. When DPIP was added in cuvettes in which Chlorophyll was not boiled it changed colors from blue to clear, this seemed to indicate that photosynthesis was occurring and depending on the magnitude of color change, the rate in which it was occurring. The cuvette that contained unboiled chloroplast and had been exposed to the light showed the biggest change in percent transmittance, which no doubt indicates that the amount of light available effects the rate in which the light reactions occur during photosynthesis. The data showed that cuvette number 3 (unboiled/light) had the biggest increases during the interval timings beginning at 44 and ending at 53. If you compare these results to that of the others, you will see that no other recorded data came close to these numbers. This data seemed to go with my hypothesis halfway, the data agreeing with my hypothesis but at the same time contradicting it. Photosynthesis did in fact occur in a cuvette but for others it did not, as the data shows it all depended on the...