Short answers, pulled from the story.
Molecular biology is a branch of biology that seeks to understand the molecular structures and chemical processes underlying biological activity within and between cells. It centers largely on nucleic acids such as DNA and RNA, and on proteins, examining how they orchestrate processes like replication, transcription, and translation.
The English physicist William Astbury first used the term molecular biology in 1945. He described it as an approach focused on uncovering the physical and chemical structures of biological molecules and how their interactions explain the observations of classical biology.
In 1953, Francis Crick, James Watson, Rosalind Franklin, and their colleagues at the Medical Research Council Unit, Cavendish Laboratory, were the first to describe the double helix model for the chemical structure of DNA. Watson and Crick were awarded the Nobel Prize in Physiology or Medicine in 1962, along with Maurice Wilkins.
The Hershey-Chase experiment confirmed that DNA is the genetic material that causes infection. Alfred Hershey and Martha Chase tagged a bacteriophage's protein coat with radioactive sulfur and its DNA with radioactive phosphorus, and found that E. coli cells showed radioactive phosphorus, proving the transformed material was DNA, not protein.
Polymerase chain reaction, or PCR, is a technique for copying DNA that allows a specific sequence to be copied or modified. Under perfect conditions it could amplify one DNA molecule into 1.07 billion molecules in less than two hours, and it is used to study gene expression, detect pathogens, and introduce mutations.
The Bradford assay enables fast, accurate quantitation of protein molecules using a dye called Coomassie Brilliant Blue G-250, which shifts from reddish-brown to bright blue upon binding protein. It was developed in 1975 by Marion M. Bradford and resists interference from molecules such as ethanol, sodium chloride, and magnesium chloride.