Photosynthesis ‘Life is a tiny electric current kept moving by the sun’ Svent Gorki
Feb 24, 2016
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
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 IndependentStage
6 CO2
6H2OC6H12O6
24 H 6O2
Oxygen produced
12H2O
SUN
Chlorophyll
Water used
Lightdependent
Stage
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.