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By : Risini Udawatte, Muhyi Khan, Jaclyn Guest
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•Refuted Ingenhousz's hypothesis
-Carbon dioxide was split into carbon and oxygen
-Carbon was used for the plants growth
-Oxygen was expelled as waste
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Study purple and green sulfur bacteria Used Close containers Purple bacteria grew proportional to
the sulfide 2 H2A + CO2 → 2A + CH2O + H2O
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• Carbon was not split to produce oxygen
• Oxygen is derived from the water in green plants
All photosynthesis require the same photochemical mechanism
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He used ‘heavy water’,H2O18, to yield 18O2 gas in his experiment.
• His experiment showed that oxygen gas produced in photosynthesis comes from water
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Kamen discovered all of the oxygen released in photosynthesis comes from water, not CO2.
He produced a radioactive isotope of carbon that could be used as a tracer in investigating chemical reactions in photosynthesis.
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1939–1941: Ruben, Kamen and the discovery of carbon-14
• experiments on tracing the path of carbon in algae by using radioactive 11CO2 (half life, 20 min), but the results were not conclusive
• set out to discover the path of carbon in photosynthesis by incorporating the short-lived radioactive isotope Carbon – 11
• CO2 can occur in the dark and may involve processes similar to bacterial systems
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• http://www.life.illinois.edu/govindjee/Part3/9_Gest_On_Ruben.pd
• Ruben, S.; Kamen, M. D. (1941), "Long-Lived Radioactive Carbon: C14", Physical Review 59 (4): 349–354Photosynthesis and phosphorylation. J. Am. Chem. Soc
.65: 279-282. 1943.
Govindjee. Bioenergetics of Photosynthesis. New York: Academic Press, 1975.
Gregory, R.P.F. Biochemistry of Photosynthesis. Belfast: Universities Press, 1971.
Rabinowitch, Eugene and Govindjee. Photosynthesis. New York: John Wiley & Sons, Inc., 1969.