Molecular Biology

DEFINITION of 'Molecular Biology'

The study of biology and biological processes at the fundamental molecular level. Molecular biology aims at understanding interactions between the primary components of cells, which include:

  • DNA (deoxyribonucleic acid) – the repository of genetic information and the chemical that makes up the genetic material of all cellular organisms;
  • RNA (ribonucleic acid) – a single stranded nucleic acid molecule whose functions range from acting as a temporary copy of DNA to structural and enzymatic functions;
  • Proteins – the major structural and enzymatic type of cell molecule, whose function depends on its three-dimensional structure that is in turn determined by its amino acid composition.

BREAKING DOWN 'Molecular Biology'

Molecular biology is not an isolated field but overlaps significantly with other areas of science such as genetics and chemistry. Molecular biology has created such a vast repository of information in recent years that it has spurred the growth of other fields like bioinformatics and computational biology, which use quantitative techniques and advanced computer technology to process and analyze this information.

Molecular biologists have learned to isolate and manipulate molecular components of cells over the decades using a number of techniques, some of which are –

  • Polymerase chain reaction (PCR): This is a robust technique for copying a DNA sequence multiple times or altering it as required.
  • Gel electrophoresis: A technique that separates DNA, RNA and proteins using an electric field, and is one of the main tools used in molecular biology.
  • Expression cloning: This is a basic technique to study protein function, and involves cloning DNA coding for a specific protein so that it can be studied in detail.
  • Arrays: This technique involves putting down a large quantity of very small spots on a single slide, with each spot having a DNA fragment molecule corresponding to a single DNA sequence. Multiple arrays are useful for comparing how genes are expressed in different tissues, such as a healthy and diseased one. Arrays can also use other molecules apart from DNA.