Oparin, Alexander Ivanovich (1894-1980), a Soviet biochemist, is best known for his theory on the origins of life on earth from chemical substances. Oparin also helped lay the technical basis for industrial biochemstry in the Soviet Union.

A 1912 graduate of the Second Moscow Gymnasium (preparatory school), he supported himself while studying at Moscow State University by working in a pharmaceutical factory. This practical industrial training helped launch Oparin's career as a Soviet scientist. When the All-Russian Union of Chemical Industry Workers held its first convention in 1918, Oparin, having been selected as the delegate of the pharmaceutical factory, was elected to the central committee.

After graduating in 1917, Oparin became a graduate student in its department of plant physiology. The following year, he asked to be sent abroad to work with Aleksei N. Bakh, who, having settled in Geneva in 1894, had in the intervening years earned international renown as a researcher in medical and agricultural chemistry. Oparin had been unaware that Bakh, a revolutionary in czarist times, who had left Russia in 1885, had returned after the collapse of the czarist government in February 1917. Oparin and Bakh soon met, and the older scientist took the younger man under his wing. Bakh, who had recently helped organize the chemical section of the National Economic Planning Council to organize the Russian chemical industry, appointed Oparin to it (1919–1922). He also appointed Oparin to the Central Chemical Laboratory (1921–1925), where Bakh served as founding director.

Despite his lengthy association with Moscow State University, Oparin never earned a regular graduate degree there. According to one source, after becoming a professor in 1929 in the university's biochemistry department, he served as its chairman for 23 years (1937–1960). According to a second source, he chaired the department of plant biochemistry (1942–1960).

Bakh's rise within the administration of the Communist Party, which he joined in 1927, smoothed the way for his protégé, Oparin. After Bakh took the lead in organizing food industry research in the late 1920's, Oparin was appointed a professor of technical biochemistry at the D. I. Mendeleev Institute of Chemical Technology in Moscow (1929–1931) and at the Moscow Institute of Grain and Flour (1930-31), where he did biochemical research on tea, sugar, flour, and grains, and at the Moscow Technical Institute of Food Production (1937–1949), where he also researched nutrition and vitamins. Oparin also was appointed assistant director in charge of science and head of the biochemical laboratory at the Central Institute of the Sugar Industry in Moscow (1927–1934). In 1934, five years after Bakh became one of the first Communists elected to the Soviet Academy of Sciences, Oparin—without ever having defended a dissertation—was awarded a doctorate in biological sciences by the academy's presidium.

As head of the academy's Laboratory of Biochemistry (1931–1935), Bakh placed Oparin in charge of scientific research; as director of its Institute of Biochemistry (1935–1946), he chose Oparin as associate director. At the beginning of Bakh's tenure as academician-secretary of the chemical sciences division of the academy (1939–1945), Oparin was elected a corresponding member of the academy's mathematical and natural science division, in plant biochemistry. After Bakh's death in May 1946, Oparin became director for the rest of his life of the Institute of Biochemistry, which was renamed the A. N. Bakh Institute of Biochemistry. Later in 1946, Oparin became a full member in the academy's division of biological sciences.

Oparin's earliest scientific publication, on free amino groups in plants, dates from 1917, the year of his graduation from Moscow State University. Although over the following 20 years he continued to study plant enzymes and their role in metabolism, and to publish his results in professional and popular journals, the main intellectual focus of his career was the problem of the origin of life. First introduced at a 1922 meeting of the Russian Botanical Society, Oparin's theory argues that simple one-celled forms of life might have come from simple organic molecules present in the early earth's atmosphere. Drawing on geological evidence, Oparin proposed that the early atmosphere of earth differed markedly from the modern atmosphere, and consisted of methane, ammonia, water vapor, and hydrogen. Oparin argued that as chemicals mixed together over time, they formed more complex chemicals. After the passage of eons, complex organic chemicals formed. This laid the foundation for the gradual emergence of life forms.

Oparin's theory, which was published in 1924, went largely unnoticed at the time, although in 1929 British biochemist J. B. S. Haldane proposed that life originated in a hot, dilute soup, which might have arisen when the early atmosphere was subjected to ultraviolet radiation and to heat from the cooling earth. Much more interest into the question of the origins of life on earth was stimulated by Oparin's 1936 book. The Origin of Life on Earth. This short book expanded on his initial theory, by taking into account not only current international research in astronomy, geochemistry, organic chemistry, and plant enzymology, but also the Communist Party line of dialectical materialist analysis, which attacked spontaneous generation and advocated the biological laws of natural selection. Subsequent Russian editions of the book (1941, 1957) not only put forth the view that metabolism is the central characteristic of life but also played down the growing assertions that genes play a vital role in the origin and evolution of life. Despite the increasing tendentiousness of Oparin's thesis, he made a lasting contribution to science with the 1936 book. Its hypothetical but plausible scenario for the emergence of metabolizing entities on a hitherto lifeless earth helped make the origin of life a modern scientific problem.

The first experimental evidence for the chemical emergence of life theory came nearly 20 years after the publication of The Origin of Life. In 1953, American chemist Stanley Miller at the University of Chicago passed electric discharges, similar to miniature thunderstorms, through a mixture of ammonia, hydrogen, methane, and water. After a week, amino acids, and other simple biochemical compounds had formed.

When Russian geneticist and agronomist Trofim Denisovich Lysenko became director of the Institute of Genetics of the Soviet Academy of Sciences in 1940, Oparin was among his ardent supporters. As the academy's chief administrator of biology (1948–1955), Oparin collaborated in Lysenko's rejection of accepted Mendelian theory, which gravely hampered scientific and agricultural progress in the USSR. With the rise of Khrushchev following Stalin's death in 1953, Lysenkos star began to wane, and hundreds of scientists signed a petition demanding Oparin's removal from his post as an academician-secretary in the academy's biology division. He was replaced in 1956. Oparin seems not to have participated in the debates that ultimately led to Lysenko's dismissal in 1965.

Although many Soviet scientists continued to distrust him because of his involvement with Lysenkoism, Oparin did not fall out of favor with the Soviet regime. His international stature, reflected in his election to the presidency of the International Biochemical Society (1959), was matched by his preferment at home. Appointed to the Supreme Soviet of the Russian Soviet Federated Socialist Republic (1951–1959), he also served on its presidium (1955–1959). He represented the Soviet Union at the World Peace Council (1950–1959) and other international scientific and political organizations, and won many Soviet awards, including the Order of Lenin (1964), Hero of Socialist Labor (1969), and the Lenin Prize (1974).

Ill health dogged Oparin in his final years, and his death in 1980 was probably the result of a heart attack. To commemorate the centennial of his birth, in 1994 the Third Trieste Conference on Chemical Evolution was subtitled the Alexander Ivanovich Oparin 100th Anniversary Conference. The International Society for the Study of the Origin of Life, whose first president he became in 1970, continues to award the Alexander Ivanovich Oparin Medal in his honor.