Hey everyone, We did an experiment a while back to test the affect of increased concentrations of chloroplast on photosynthetic activity. It seemed intuitive to think that increased chloroplast concentration would yeild increased photosynthetic activity. To measure photosynthetic activty we used DPIP and a photospectrometer. As we increased chloroplast concentration, the measured absorbance decreased (indicating increased photosynthetic activity), however at a point, the absorbance began to rise (indicating decreased photosynthetic activty). We found this odd and are having trouble explaining it. Anyone have any ideas? Could it just be something to do with the DPIP? Thanks for any help!