The Calvin Cycle was proposed by Melvin Calvin, who using the Lollipop experiment was able to infer which carbon compound in the light dependent reaction of plant cells was being expressed.


  1. Green Algae (Chlorella) is placed within a thin transparent container (the lollipop container)
  2. Radioactive carbon-14 is added to the apparatus
  3.  Bright light is shone onto the sample
  4. At 5 second intervals the samples of algae are dropped into hot methanol to stop the chemical reaction instantly
  5. The Dead algal samples are analysed using 2 way chromatography, which separates out the different carbon compounds

Through varying the time between the light being on and the reaction being halted it can be determined the different carbon compositions that are occuring in the algae at that moment. 

Time (s)Substances found to be radioactive
0Carbon Dioxide
5Glycerate 3-phosphate
10Glycerate 3-phosphate + triose phosphate
15Glycerate 3-phosphate + triose phosphate + glucose
20Glycerate 3-phosphate + triose phosphate + glucose + ribulose bisphosphate