- Born:
- April 8, 1911, St. Paul, Minnesota, U.S.
- Died:
- January 8, 1997, Berkeley, California (aged 85)
- Awards And Honors:
- National Medal of Science (1989)
- Nobel Prize (1961)
- Subjects Of Study:
- Chlorella
- origin of life
- photosynthesis
- radiation chemistry
Melvin Calvin
-
Who was Melvin Calvin?
Melvin Calvin (1911-1997) was an American biochemist renowned for his groundbreaking research on the chemical pathways of photosynthesis, for which he received the Nobel Prize in Chemistry in 1961.
After earning a Ph.D. from the University of Minnesota in 1935, Calvin joined the faculty of the University of California, Berkeley, in 1937. There, he delved into various fields, including molecular genetics and oxygen-generating apparatuses for submarines during World War II. In 1946, Calvin began his Nobel prize-winning work on photosynthesis, tracing the path of carbon and discovering the Calvin cycle.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What scientific field did Melvin Calvin work in?
Melvin Calvin was an American biochemist who won the 1961 Nobel Prize in Chemistry for discovering the chemical pathways of photosynthesis. His work involved the use of carbon-14 to trace the path of carbon in plants, which led to the discovery of the Calvin cycle, a series of chemical reactions that occur during photosynthesis.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What important process in plants did Melvin Calvin study?
Melvin Calvin studied the chemical pathways of photosynthesis. In 1946, Calvin began to investigate the process by adding carbon dioxide with radioactive carbon-14 to green algae. He halted the algae's growth at different stages and then isolated and identified the radioactive compounds. This allowed him to identify the chemical reactions in the intermediate steps of photosynthesis. His work led to the discovery of the Calvin cycle, where carbon dioxide is converted into carbohydrates. For this achievement, he received the Nobel Prize in Chemistry in 1961.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What is the Calvin cycle, and why is it important?
The Calvin cycle, also known as the Calvin-Benson cycle, is the key step of the dark reactions in photosynthesis. During the cycle, the enzyme RuBisCO attaches carbon dioxide ($CO_2$) to RuBP, a five-carbon compound. This creates an unstable six-carbon molecule that splits into two three-carbon compounds. ATP and NADPH then convert these three-carbon compounds into a high-energy sugar molecule, which can be used to form glucose and other carbohydrates. The rest is recycled, regenerating RuBP with ATP so the cycle can continue.
The Calvin cycle is vital because it is the primary way that plants and other photosynthetic organisms convert carbon dioxide into sugars, which are then used for energy and building blocks for growth. Melvin Calvin received the 1961 Nobel Prize in Chemistry for discovering the chemical pathways of photosynthesis, including the Calvin cycle.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How did Melvin Calvin use radioactive carbon in his experiments?
Melvin Calvin utilized radioactive carbon-14 to elucidate the chemical pathways of photosynthesis. In his experiments, green plants photosynthesized in the presence of carbon dioxide containing radioactive carbon-14. By halting the process at different stages and using paper chromatography, Calvin identified and isolated minute quantities of radioactive compounds.
Key findings from Calvin's work:
- Radioactive products, including 3-phosphoglycerate (PGA), sugar phosphates, amino acids, sucrose, and carboxylic acids, became labeled during the process.
- PGA was identified as the first stable compound formed during carbon dioxide fixation in green plants.
- Further studies led to mapping the carbon fixation and reduction pathway, known as the Calvin-Benson cycle.
His innovative use of carbon-14 as a tracer to explain a chemical pathway earned him the Nobel Prize in Chemistry in 1961.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How did Melvin Calvin's discoveries change our understanding of photosynthesis?
Melvin Calvin's work with radioactive carbon-14 revolutionized the understanding of photosynthesis. By using carbon dioxide with trace amounts of radioactive carbon-14, he traced the path of carbon during photosynthesis in green algae. Calvin identified 3-phosphoglycerate (PGA) as the first stable compound formed during carbon dioxide fixation, revealing the crucial role of the Calvin cycle in converting carbon dioxide into carbohydrates. His work provided insight into the "dark" reactions of photosynthesis, which are impelled by compounds produced during the "light" reactions. This was the first use of a carbon-14 tracer to explain a chemical pathway.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Melvin Calvin (born April 8, 1911, St. Paul, Minnesota, U.S.âdied January 8, 1997, Berkeley, California) was an American biochemist who received the 1961 Nobel Prize for Chemistry for his discovery of the chemical pathways of photosynthesis.
Calvin was the son of immigrant parents. His father was from Kalvaria, Lithuania, so the Ellis Island immigration authorities renamed him Calvin; his mother was from Russian Georgia. Soon after his birth, the family moved to Detroit, Michigan, where Calvin showed an early interest in science, especially chemistry and physics. In 1927 he received a full scholarship from the Michigan College of Mining and Technology (now Michigan Technological University) in Houghton, where he was the schoolâs first chemistry major. Few chemistry courses were offered, so he enrolled in mineralogy, geology, paleontology, and civil engineering courses, all of which proved useful in his later interdisciplinary scientific research. Following his sophomore year, he interrupted his studies for a year, earning money as an analyst in a brass factory.
Calvin earned a bachelorâs degree in 1931, and then he attended the University of Minnesota in Minneapolis, from which he received a doctorate in 1935 with a dissertation on the electron affinity of halogen atoms. With a Rockefeller Foundation grant, he researched coordination catalysis, activation of molecular hydrogen, and metalloporphyrins (porphyrin and metal compounds) at the University of Manchester in England with Michael Polanyi, who introduced him to the interdisciplinary approach. In 1937 Calvin joined the faculty of the University of California, Berkeley, as an instructor. (He was the first chemist trained elsewhere to be hired by the school since 1912.) He rose through the ranks to become director (1946) of the bioorganic chemistry group at the schoolâs Lawrence Radiation Laboratory (now the Lawrence Livermore National Laboratory), director of the Laboratory of Chemical Biodynamics (1963), associate director of Lawrence Livermore (1967), and University Professor of Chemistry (1971).
At Berkeley, Calvin continued his work on hydrogen activation and began work on the colour of organic compounds, leading him to study the electronic structure of organic molecules. In the early 1940s, he worked on molecular genetics, proposing that hydrogen bonding is involved in the stacking of nucleic acid bases in chromosomes. During World War II, he worked on cobalt complexes that bond reversibly with oxygen to produce an oxygen-generating apparatus for submarines or destroyers. In the Manhattan Project, he employed chelation and solvent extraction to isolate and purify plutonium from other fission products of uranium that had been irradiated. Although not developed in time for wartime use, his technique was later used for laboratory separations.
In 1942 Calvin married Genevieve Jemtegaard, with later Nobel chemistry laureate Glenn T. Seaborg as best man. The married couple collaborated on an interdisciplinary project to investigate the chemical factors in the Rh blood group system. Genevieve was a juvenile probation officer, but, according to Calvinâs autobiography, âshe spent a great deal of time actually in the laboratory working with the antigenic material. This was her first chemical laboratory experience but not her last by any means.â Together they helped to determine the structure of one of the Rh antigens, which they named elinin for their daughter Elin. Following the oil embargo after the 1973 Arab-Israeli War, they sought suitable plants, e.g., genus Euphorbia, to convert solar energy to hydrocarbons for fuel, but the project failed to be economically feasible.
In 1946 Calvin began his Nobel prize-winning work on photosynthesis. After adding carbon dioxide with trace amounts of radioactive carbon-14 to an illuminated suspension of the single-cell green alga Chlorella pyrenoidosa, he stopped the algaâs growth at different stages and used paper chromatography to isolate and identify the minute quantities of radioactive compounds. This enabled him to identify most of the chemical reactions in the intermediate steps of photosynthesisâthe process in which carbon dioxide is converted into carbohydrates. He discovered the âCalvin cycle,â in which the âdarkâ photosynthetic reactions are impelled by compounds produced in the âlightâ reactions that occur on absorption of light by chlorophyll to yield oxygen. Also using isotopic tracer techniques, he followed the path of oxygen in photosynthesis. This was the first use of a carbon-14 tracer to explain a chemical pathway.
Calvinâs research also included work on electronic, photoelectronic, and photochemical behaviour of porphyrins; chemical evolution and organic geochemistry, including organic constituents of lunar rocks for the U.S. National Aeronautics and Space Administration (NASA); free radical reactions; the effect of deuterium (âheavy hydrogenâ) on biochemical reactions; chemical and viral carcinogenesis; artificial photosynthesis (âsynthetic chloroplastsâ); radiation chemistry; the biochemistry of learning; brain chemistry; philosophy of science; and processes leading to the origin of life.
Calvinâs bioorganic group eventually required more space, so he designed the new Laboratory of Chemical Biodynamics (the âRoundhouseâ or âCalvin Carouselâ). This circular building contained open laboratories and numerous windows but few walls to encourage the interdisciplinary interaction that he had carried out with his photosynthesis group at the old Radiation Laboratory. He directed this laboratory until his mandatory age retirement in 1980, when it was renamed the Melvin Calvin Laboratory. Although officially retired, he continued to come to his office until 1996 to work with a small research group.
Calvin was the author of more than 600 articles and 7 books, and he was the recipient of several honorary degrees from U.S. and foreign universities. His numerous awards included the Priestley Medal (1978), the American Chemical Societyâs highest award, and the U.S. National Medal of Science (1989), the highest U.S. civilian scientific award.
