Molecular Biology is the study of molecular underpinning the process of replication, transcription, translation and cell function. It mainly deals with the DNA, RNA, and protein; their structure, function, role, and bio-synthesis. The main pillars for the foundation of molecular biology are biochemistry and genetics besides biophysics. The term “molecular biology” was coined in 1938 by Warren Weaver, director of Natural Sciences for the Rockefeller Foundation.

The roots of molecular biology were established in 1953 when an Englishman, Francis Crick and a young American, James Watson working at Medical Research Council Unit, Cavendish Laboratory, Cambridge, proposed a double helical model for the structure of DNA which was well known as the chemical bearer of genetic information.

Simply, the process of transferring the DNA information present in DNA to the RNA (rRNA, mRNA and tRNA) is called transcription and the process of transferring genetic message encoded in mRNA to the amino acid of the linear polypeptide is called translation. Replication is the process of formation of exactly similar information carrying sister DNA molecules. The overall process of replication, transcription and translation is called central dogma in molecular biology.

Schematic relationship between Replication, Translation and Transcription

DNA (Deoxyribonucleic acid) is a chemical unit carrying the genetic information in almost all organisms (exception viruses) chiefly made up of phosphate backbone, deoxy-ribose sugar and nitrogen bases (Adenine, Guanine, Cytosine and Thiamine). On the other hand, RNA (Ribonucleic acid) is a single stranded or double stranded molecule made up of phosphate, a ribose sugar and nitrogen bases (Adenine, Guanine, Cytocine and Uracil). It is the genetic material of some plant viruses (e.g., Tobacco Moisac Virus, Turnip Yellow Moisac Virus), animal virus (e.g., Influenza viruses, rous sarcoma viruses) and bacteriophages (e.g., MS2).

The fields of molecular biology are it’s own but often combine with biochemistry and genetics. Biochemistry and genetics are two distinct disciplines; biochemistry deals with the structure, function and role of biomolecules whereas genetics deals with the study of heredity and the variation of inherited characteristics. Molecular biology is also mutually related to computer science as bioinformatics and computational biology in a quantitative manner.

Schematic diagram of the relation between Molecular biology, Biochemistry and Genetics

Since the late 1950s and early 1960s, molecular biologist learned to isolate, characterized and manipulate the molecular components (DNA, RNA, and proteins) of the cells and organisms. Before 2000, researchers and scientists from the globe merely focused on the structure and function of DNA, molecular genetics and their role in the cell, developmental, and evolutionary biology. After that, the genetic engineering by manipulation of DNA to the cell and/or organisms became the most interested and researched sector.

Materials and methods in Molecular biology

Variety of microorganisms are used in molecular biology like bacteria, bacteriophages, viruses and simple eukaryotes such as Escherichia coli, unicellular green algae, yeast, Neurospora, larval salivary gland chromosomes of Dipteran insect (Drosophila) and lampbrush chromosomes of oocytes of different amphibians and other higher animals.

A wide array of bio-physicochemical techniques (electron microscopy, ultracentrifugation, colourimetry, spectrophotometry, chromatography, isotopic tracers, X-ray crystallography, electrophoresis etc.) are used in molecular biology but major molecular techniques are -

  • · Molecular cloning
  • · Polymerase Chain Reaction (PCR)
  • · Gel Electrophoresis
  • · Macromolecule blotting and probing
  • · Macro-array
  • · Allele-specific oligonucleotide
  • · Antiquated technologies

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