Question

1. How does gene expression initiate?

2. What are the key steps in gene expression?

Answer 1

Gene encodes the genetic information and gene expression is the process by which the genetic code which is mainly the nucleotide sequence - of a gene is used to direct protein synthesis which in turn regulate the various metabolic processes in any organisms.

Gene expression initiates during the transcription process. The first step of transcription is known as initiation. During initiation the DNA molecule unwinds and separates to form a small open complex. RNA polymerase binds to the promoter of the template strand and RNA synthesis starts from here. After this elongation starts till the stop codon where terminations of transcription process takes place.

The process of gene expression involves the following main events.

Transcription is the process through which messenger RNA (mRNA) are transcribed from the gene of interest (DNA) by the enzyme RNA polymerase. The mRNA contains the introns (non coding region) and exons (coding region which determines the sequence of amino acids). The introns are removed through splicing. The transcription further had four major steps which are initiation, elongation, termination and processing

Translation is the process through which spliced mRNA are used to synthesised protein and the subsequent post-translational processing of the protein molecule. Some genes are responsible for the production of other forms of RNA that play a role in translation, including transfer RNA (tRNA) and ribosomal RNA (rRNA). Translation also have four steps- initiation, elongation, termination and post translations protein processing.