I predicted that if the decolorization of DPIP is caused by photosynthesis and not cell respiration and spinach extract containing chloroplasts and mitochondria is incubated with DPIP, then the rate of DPIP decolorization should be higher if in bright light verses dark light because DPIP is reduced by photosynthesis and not by the mitochondria or any other cellular function. If DPIP was only decolorized by chloroplasts, then the percent transmittance of chloroplast suspensions would be a lot higher than the data we collected. If DPIP was only decolorized by mitochondria, then the percent transmittance of chloroplast suspensions would end up looking like a straight, horizontal line across the graph because photosynthesis would not occur without the chloroplasts. If DPIP was decolorized by both mitochondria and chloroplasts, then the percent transmittance of chloroplast suspensions would be a gradual increase, and the graph would be a line going up at a steady rate. The data I collected does not support my hypothesis because I said the rate of DPIP decolorization should be higher if in bright light verses dark light, and based on the look of my graph, my hypothesis was incorrect because Cuvette 3 and 4 (unboiled/light and boiled/light) do not both have a higher percent transmittance. Cuvette 3 does have a higher transmittance, however Cuvette 4 stays for the most part, the same and does not have an increase in percent transmittance. For Cuvette 2 (unboiled/dark), from 0 to 5 minutes, it increased fast but then leveled off from 5 to 15 minutes. Cuvette 3 (unboiled/light), it had a steady but fast increase for the entire amount of time, from 0 to 15 minutes. Cuvette 4 (boiled/light) it had a very slight increase from 0 to 5 minutes, but then mostly leveled off from 5 to 15 minutes. Cuvette 5 (no chloroplasts) actually had a very slight decrease in the transmittance, but for the most part stayed leveled off. The graph looks as it was expected to look with...
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