RuBisCo levels in Quercus rubra: Senescencing leaves vs. Photosynthetic leaves
John Herlihy, Sammy Mainiero, Elizabeth Hubbard, and Dr. Terrie Rife
Department of Biology, James Madison University, 2010
Introduction Methods Results Discussion Literature Cited
Abstract
Ribulose 1,5-biphosphate carboxylase, or RuBisCo, is the most abundant protein on our planet. This enzyme catalyzes the first step in carbon fixation in which carbon dioxide is added to ribulose 1,5-biphosphate, a five-carbon sugar. In this experiment, we examined the amount of RuBisCo present in leaves of the Quercus rubra, or red oak, tree. Three types of leaves were examined: green photosynthetic leaves and senescent leaves that were still attached to the tree (red) or detached before collection (brown). It was hypothesized that RuBisCo is most abundant in green leaves and least abundant in brown leaves and further hypothesized that the amount of RuBisCo DNA would not differ between the samples since all leaves came from the same tree. A DC protein assay and Western Blot were used to quantify the RuBisCo protein in each of the three leaves. Real time PCR was then used to determine the amounts of RuBisCo DNA present within each sample. RuBisCo protein and DNA were only present in the green leaf sample. This corresponded with our hypothesis as leaf senescence had already begun to break down chloroplast proteins and DNA.
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