Editing Martin Kamen (section)

==Research==
Although carbon-14 was previously known, the discovery of the synthesis of carbon-14 occurred at Berkeley in 1940 when Kamen and [[Sam Ruben]] bombarded [[graphite]] in the cyclotron in hopes of producing a radioactive isotope of [[carbon]] that could be used as a [[radioactive tracer|tracer]] in investigating chemical reactions in [[photosynthesis]]. Their experiment resulted in production of carbon-14.<ref name=guardian>{{cite news|last=Wright |first= Pierce|work=[[The Guardian]]|date=September 9, 2002 |url=https://www.theguardian.com/news/2002/sep/09/guardianobituaries.obituaries1|title=Martin Kamen|access-date=December 26, 2019}}</ref><ref name="Benson">{{cite journal |last1=Benson |first1=A. A. |title=Paving the Path |journal=Annual Review of Plant Biology |date=June 2002 |volume=53 |issue=1 |pages=1–25 |doi=10.1146/annurev.arplant.53.091201.142547 |pmid=12221968 |s2cid=5780582 |doi-access=free }}</ref><ref name="AR1986"/>
By bombarding matter with particles in the [[cyclotron]], [[radioactive isotopes]] such as carbon-14 were generated. Using carbon-14, the order of events in biochemical reactions could be elucidated, showing the precursors of a particular biochemical product, revealing the network of reactions that constitute life.<ref name="Powell">{{cite book |last1=Powell |first1=Jonathan |title=From Cave Art to Hubble: A History of Astronomical Record Keeping |date=20 November 2019 |publisher=Springer Nature |isbn=978-3-030-31688-4 |page=222 |url=https://books.google.com/books?id=_L-_DwAAQBAJ&pg=PA222 |access-date=15 August 2022 |language=en}}</ref>

Kamen confirmed in 1941 that all of the [[oxygen]] released in [[photosynthesis]] comes from water, not [[carbon dioxide]].<ref name="Rastogi">{{cite book |last1=Rastogi |first1=V. B. |title=Modern Biology |date=1997 |publisher=Pitambar Publishing |isbn=978-81-209-0496-5 |page=I-86 |url=https://books.google.com/books?id=D-85x6Jhji0C&pg=SA1-PA86 |access-date=12 August 2022 |language=en}}</ref><ref name="Nickelsen">{{cite book |last1=Nickelsen |first1=Kärin |title=Explaining Photosynthesis: Models of Biochemical Mechanisms, 1840-1960 |date=17 June 2015 |publisher=Springer |isbn=978-94-017-9582-1 |pages=201–214 |url=https://books.google.com/books?id=XOfyCQAAQBAJ&pg=PA213 |access-date=12 August 2022 |language=en}}</ref> He also studied anoxygenic photosynthetic bacteria, the biochemistry of [[cytochromes]] and their role in photosynthesis and [[metabolism]], photosynthetic bacteria,<ref name="Govindjee"/> the role of [[molybdenum]] in biological [[nitrogen fixation]], the role of iron in the activity of [[porphyrin]] compounds in plants and animals, and [[calcium]] exchange in cancerous [[tumor]]s,<ref name="Irish">{{cite news |title=Carbon-14 discoverer who was harassed as communist |url=https://www.irishtimes.com/news/carbon-14-discoverer-who-was-harassed-as-communist-1.1096218 |access-date=15 August 2022 |newspaper=The Irish Times |date=September 21, 2002 |language=en}}</ref> making substantial contributions.<ref name="Govindjee"/>