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Cell Fractionation Lab Report

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The information in this graph is based off of the data in Figure 1.1 but this graph is showing the absolute value of the changes of the absorbance in each cell fraction over a fourteen-minute time interval. Since DCIP directly indicates the amount of mitochondria present, the greater the decrease of DCIP absorbance, the greater the number mitochondria are present in the cell fraction.

The goal from experiment one was to figure out which cell fractionations have the highest amount of mitochondria present. To go about accomplishing this goal we fractionated the cell components through a process of differential centrifugation which separates structures by size and density (McAllister & Leicht p.42). The first pellet (P1) was centrifuged at 600 x g for 2 minutes and pulled down mostly …show more content…

The second pellet (P2) was centrifuged for 5 minutes at 2000 x g. The third pellet (P3) was centrifuged at 21,000 x g for 15 minutes. The supernatant from the third pellet formed the third supernatant (S3). After obtaining P1, P2, P3, and S3, the goal of part 2 of experiment 1 was to figure out which cell fraction has the highest amount of mitochondria. DCIP, which is an electron acceptor, was added to P1, P2, P3, and S3 to test for SDH, a biochemical marker for the presence of functional mitochondria (McAllister & Leicht p.71). DCIP changed from blue to colorless when electrons are being reduced, indicating a high SDH activity level and a large presence of mitochondria. The amount of color change is proportional to the amount of SDH enzyme and the amount of mitochondria in a cell fraction (McAllister & Leicht p.71). Blank cuvettes containing assay buffer, sodium azide, and a

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