Molecular biology resources

Molecular biology is a branch of science which studies biological systems at a molecular level. The purview of molecular biology often overlaps with fields such as biochemistry and genetics, since molecular biology closely studies cell systems and their complex interactions. Protein biosynthesis, DNA, and RNA patterns are also explored by molecular biologists.

History of Molecular Biology

The name molecular biology was coined in 1938 by Warren Weaver of the Rockefeller Foundation’s Natural Sciences department. Though studies in molecular biology started as early as the 1930s, it was not until the 1950s that major strides were taken in the field. The Rockefeller institute helped popularize molecular biology by funding several molecular biology research projects. The advances in X-ray crystallography contributed greatly to the field of molecular biology as well. In the 1960s, biologists finally succeeded in isolating, characterizing, and even manipulating molecular cell components such as DNA.

The Central Dogma of Molecular Biology

In 1958, Francis Crick articulated the central dogma of molecular biology. Subsequently, he re-stated the central dogma in 1970. The central dogma explains the sequential information transfer in terms of detailed residue transfer. It also states that information cannot be re-transferred from protein to nucleic acid or protein. To better understand the framework of sequential information transfers comprising of biopolymers, the central dogma is often used. The central dogma also categorizes the biopolymers into three groups, namely the DNA, RNA, and the proteins. Furthermore, the central dogma further sub-divides the groups into three classes: the 3 general transfers, the three special transfers, and the three unknown transfers.

Molecular Biology Techniques

There are a number of important molecular biology techniques which help scientists to isolate or manipulate the molecular cell components.

  • Expression Cloning – This method is considered a basic technique for studying protein functions. In this technique, the protein’s DNA coding is cloned into an expression vector called a plasmid. This plasmid may or may not contain promoter elements for producing a protein of interest.
    • Expression Cloning: Expression cloning of a rat B2 bradykinin receptor.
  • Polymerase Chain Reaction – This technique is used for DNA copying since it’s very versatile. In PCR, a DNA sequence can be easily copied thousands of times or can even be altered.
    • Polymerase Chain Reaction: A comprehensive PCR and Multiplex PCR Guide.
  • Gel Electrophoresis – This technique is based on the premise that electric fields can separate proteins, DNA, and RNA molecules. The agarose gel electrophoresis is the technique wherein agarose gel is used to separate RNA and DNA.
    • Gel Electrophoresis Virtual Lab: How gel electrophoresis is used in forensics.
  • Southern Blotting – Southern Blotting is the technique for finding out a particular DNA sequence which is present in a DNA sample. After the DNA samples are separated by gel electrophoresis, they are passed on to a membrane by blotting.
    • Southern Blot Method: A brief overview of a Southern Blot technique.
  • Northern Blotting – The northern blotting technique helps in a better understanding of a specific RNA molecule’s expression patterns.
    • Northern Blot Technique: Details RNA processing and the Northern Blot technique.
  • Western Blotting – In western blotting, small amounts of protein are injected into animal specimens such as a mouse, creating the antibodies of the proteins. When produced by using animals as agents, they are called polyclonal antibodies and when produced in cell culture, they’re known as monoclonal antibodies.
  • Eastern Blotting – A protein’s post-translational modification can be identified by the eastern blotting technique. A few specific substrates are used for probing the modifications of the blotted proteins.

Additional Information and Techniques