Mark Steven Bretscher (born 8 January 1940) is a British biological scientist and Fellow of the Royal Society.
[2] In 1961 he joined the MRC Unit for the Study of the Molecular Structure of Biological Systems in the Cavendish laboratory as a graduate student with Francis Crick and Sydney Brenner and then spent a year as a Jane Coffin Childs Fellow with Paul Berg at Stanford (1964-5).
Protein Synthesis In his first paper, on the genetic code, the word "codon" first appeared in print (inserted by Francis Crick).
[3] Bretscher later showed that the growing polypeptide chain is attached to one of the hydroxyl groups of the terminal adenosine residue of tRNA.
The presence of cholesterol makes a bilayer thicker: the increasing thickness of the membrane from cis- to trans- leads to a filtration of only those proteins having a long enough transmembrane domain to advance to the cell surface.
This circulating membrane is restricted to a few proteins (mainly receptors which bring nutrients, such as LDL or transferrin) into the cell and lipids.
[20] Strikingly, both Dictyostelium amoebae and neutrophils can chemotax towards a target whilst in suspension, showing that a solid substrate is not required for movement; this provides strong evidence that these cells move by a flowing membrane.