‘Life is a tiny electric current kept moving by the sun’ Svent Gorki Photosynthesis ‘Life is a tiny electric current kept moving by the sun’ Svent Gorki

Protocista Algae Plants

Photosynthesis Equation carbon dioxide + water glucose + oxygen 6CO2 + 6H20  C6H1206

White Light

Electro magnetic spectrum

So Why Green?

Chloroplasts

Fluorescence of extracted chlorophyll Chlorophyll plays an important role in photosynthesis as it absorbs the energy form the sun Fluorescence of extracted chlorophyll

Absorption and action spectrum of chlorophyll

Light Independent Stage 6 CO2 6H2O C6H12O6 24 H 6O2 Oxygen produced 12H2O SUN Chlorophyll Water used Light dependent

Measuring the rate of photosynthesis

Extraction of chlorophyll and absorption spectrum Assessment - Data Collection and Processing, Conclusion and Evaluation, manipulative skills Extraction of chlorophyll Dip fresh leaf material into boiling water first to kill the cells and to make the cell membrane fully permeable to the solvent. Finely cut about 10g of leaf material (excluding the midrib and petiole) into a mortar and add a small amount of washed and dried sand. Grind up the leaf matter with 20cm3 of propanone, using a pestle, to make a concentrated leaf extract. Either filter the pigment solution or decant it (using a glass rod to hold back the debris), and place in a small glass centrifuge tube. Centrifuge the extract briefly, in order to clear all suspended organic matter. Pour the supernatant solution into a small glass tube, seal with a bung, label it, and stand this chlorophyll extract in the dark, an ice bath, until required.

Measuring absorption of light by chlorophyll   You will be shown how to use either a colorimeter or a spectrophotometer to measure the absorption spectrum of your extract. Once you have done this you will need to plot a graph of absorption against wavelength for the data you collected. Compare this to the absorption and action spectrums of chlorophyll. How good is your match and how could the experiment be altered to improve your results.