SCIENTIFIC REPORT ON THE EFFECT OF WAVELENGTH ON PHOTOSYNTHESIS Red wavelengths will increase the rate of photosynthesis to a greater degree than blue or green wavelengths and thus will be the most optimal for plant growth. This hypothesis will be tested under laboratory conditions using silver beet extracts and DCPIP under different wavelengths and assessing the photosynthetic qualities using a spectrometer at 605nm. Photosynthesis is the process by which the suns visible light (electromagnetic radiation) is utilised by organisms with photosynthetic abilities (pigments called chloroplasts) as a chemical energy source. Living chloroplasts can be readily isolated from live plant tissue and used to investigate photosynthesis (Lilley et al. 1975; Halliwell 1984). Photosynthetic organelles are Eukaryotic and are fundamental for the survival of not only the organisms themselves, but the entire ecosystem around them as well. After the electromagnetic radiation is completely absorbed by the pigments, the electron transport chain (ETC) becomes a channel for excited electrons to pass through, capturing ATP and NADPH (Hoober, 1948) s and NADPH are then used to fix CO2 into carbohydrates (Halliwell 1984). The flow of electrons through the ETC can be monitored using the chemical DCPIP (Paterson and Arntzen 1982), which preferentially accepts electrons before the final stage of the ETC (Figure 6.1). When DCPIP is oxidised (before it accepts electrons) it is blue, but once it is reduced (has gained electrons) it turns colourless. Therefore when DCPIP is mixed with live chloroplast, the rate of change in DCPIP colour is proportional to the amount of electrons flowing through the ETC, which is in turn proportional to photosynthetic activity. The colour (and hence absorbance) of DCPIP can be measured using a spectrophotometer.
Photons (lightning bolts) are absorbed by photosystems II and I, moving electrons through the electron transport chain towards NADP+. DCPIPox is blue...
Please join StudyMode to read the full document