GENE EXPRESSION

The DNA has two important role in the cell, first is replication and the second is expression. Gene expression is accomplished by a series of events. The information contained in DNA is converted into molecules that determine the metabolism of the cell.

During the process of gene expression DNA is the first copied into an RNA molecule which determines the amino acid sequences of a molecule of a protein. The RNA molecules are synthesized by using a portion of base sequences of single strand of double stranded DNA. This single strand is called template. Hence formation of an RNA transcript is facilitated by an enzyme, RNA polymerase. Therefore the process of synthesis of an RNA molecule corresponding to a gene is called transcription. By using base sequences and RNA molecule , proteins are synthesized in a definite order. Production of an amino acid sequence from an RNA base sequence is called translation. After completion of translation proteins are synthesized. Therefore, gene expression refers to protein synthesis through two events, transcription and translation.