The science field of molecular biology is concerned with chemical structures, molecular compositions, interactions between molecules, and biological processes that involve molecules such as nucleic acids (DNA and RNA) and proteins, which are essential for cell function and maintenance. Molecular biology developed out of the related fields of biochemistry, genetics, and biophysics, emerging in the 1930s. Molecular biologists seek answers to questions about molecular structures and the association between genes and characteristics of an organism. Methods used in molecular biology, such as recombinant DNA technology, polymerase chain reaction, and DNA sequencing, allow scientists to isolate, characterize, and modify specific genes to study them.
Molecular biology attempts to describe biological phenomena in terms of molecular interactions and encompasses research from the areas of biochemistry, microbiology, genetics, and immunology. Biochemistry is focused on the chemistry of living organisms and seeks to explain the properties of living organisms in terms of their chemical substances. Molecular biology emerged when scientists with different expertise directed their attention to understanding life at a molecular level. Because molecular biologists do not necessarily have the level of chemistry training that biochemists have, there have been objections to the term “molecular biology.” Erwin Chargaff, a biochemist at Columbia University, joked that “Molecular Biology is the practice of biochemistry without a license.” On the other hand, molecular biology is a convenient term to describe a research field that combines a variety of disciplines. Francis Crick said he started calling himself a molecular biologist because “I got tired of explaining that I was a mixture of crystallographer, biophysicist, biochemist and geneticist.”
Both biochemists and molecular biologists strive to understand the basis of life. Biochemists approach this through the isolation of and characterization of chemical substances, derived from their fragmentation. Molecular biologists are usually more interested in phenomena and deal more often with whole cells and organisms. Molecular biology and biochemistry have enough in common that many departments and societies couple them together.