Molecular Biology

This is a field of science that seeks to understand the chemical structures and processes of macromolecules. The field of molecular biology is focused especially on nucleic acids (e.g., DNA and RNA) and proteins—macromolecules that are essential to life processes, and how these molecules interact and behave within cells. Molecular biology emerged in the 1930s, having developed out of the related fields of biochemistry, genetics, and biophysics; today it remains closely associated with those fields.

Techniques used in Molecular Biology

1.Polymerase chain reaction (PCR)

This is one of the most important techniques used in molecular biology and is basically used to amplify DNA into millions of DNA molecules. . PCR can also be used to introduce mutations within the DNA or introduce special restriction enzyme sites. In addition, PCR is used to determine whether a certain DNA fragment exists in a cDNA library. Different types of PCR include reverse transcription PCR (RT-PCR) for amplification of RNA and quantitative PCR (QPCR) to measure the amount of RNA or DNA present.

2.Expression cloning

This technique is used in understanding the protein function. The DNA that codes for a particular protein is cloned or copied using PCR into an expression vector called a plasmid. The plasmid is introduced to either an animal cell or a bacterial cell. This plasmid has promoter elements that can stimulate high expression of the desired protein so that its enzymatic activity can then be examined.

3.Gel electrophoresis

This technique is used in molecular biology to separate DNA, RNA, and proteins based on their size by applying an electric field as the DNA is run through agarose gel.

4.Macromolecule blotting and probing

Processes such as southern blotting, northern blotting, western blotting and, eastern blotting are used to transfer DNA or RNA proteins onto a blotting membrane (often after gel electrophoresis) so they can be stained or radioactively labeled and then visualized.

5.Arrays

A DNA microarray or DNA chip is a collection of DNA spots mounted on a solid surface such as a microscope slide that can be used to simultaneously quantify protein expression levels across a large number of genes. The technique can also be used to genotype various different genomic regions.