Mark Bretscher was born in Cambridge, UK, on 8th January 1940; he is the son of the nuclear physicist Egon Bretscher. Educated at Abingdon School, Berkshire, he went on to study Chemistry at the University of Cambridge. Bretscher moved from the Chemistry department to Biology in 1961 where he started a PhD under Sydney Brenner initially in the Cavendish Laboratory and then at the new MRC laboratory of Molecular Biology. His worked focused on the use of synthetic polyribonucleotides to investigate the genetic code. After completing his PhD in 1964, Bretscher took up a year-long Postdoctoral Fellowship at Stanford University, California with Dr. Paul Berg. Upon his return from Stanford in 1965, he continued with his work on protein biosynthesis as a Research Fellow at Gonville and Cauis College, Cambridge. In 1970, Bretscher began to feel that his work on protein biosynthesis was in an overcrowded research area, so instead switched to looking at cell membranes - a new area of study for the MRC Laboratory. From studies on human erythrocytes he was the first to show that the lipid bilayer structure for biological membranes was asymmetric, and was spanned by specific membrane proteins. From 1974-75 Bretscher took up a visiting Professorship at the Department of Biochemistry and Molecular Biology, Harvard University; here he taught a final year course on cell membranes. On returning to Cambridge, he began studies of how animal cells move. Bretscher was joint head of the Cell Biology Division at the MRC Laboratory of Molecular Biology, Cambridge from 1986 -1995, sharing the post with Peter Lawrence and then Hugh Pelham. He became a fellow of the Royal Society in 1985. Since 2005 Bretscher has been an emeritus scientist at the Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge. In 2009, he discovered that amoebae and human neutrophils (white blood cells) can swim, which he describes as, "perhaps my most important contribution yet".