REGULATION OF GENE EXPRESSION - EASY NOTES

DEFINITION:

-The combined process of transcription of information present on DNA into m-RNA and then translation of mRNA into a protein is called GENE EXPRESSION.

-Regulation of gene expression is essential for metabolic functions, growth & development, and differentiation of tissues.

-In prokaryotes, regulation of gene expression occurs at the level of transcription and mRNA synthesis

-In eukaryotes, there are two types of regulation :

POSITIVE REGULATION:

-Because of the presence of a specific regulatory element, if the expression is increased then it is called positive regulation

-Any molecule mediating the positive regulation is called as activator or inducer.

NEGATIVE REGULATION:

-Because of the presence of a specific regulatory element, if the expression is decreased then it is called negative regulation.

-Any molecule mediating the negative regulation is called a repressor.

-Some genes are expressed only in the presence of an activator or inducer such genes are called inducible genes.

-Some genes are not affected by the presence of any other molecule or their expression is not regulated at all, such genes are called constitutive genes or housekeeping genes.