Question

Describe how the genes are regulated in prokaryotes (pre and post transcriptionally).

Answer 1

Genes are regulated at the transcriptional level in prokaryotes and expression occur in response to the avalibility of nutrients. The gene regulation takes place in following ways:

I. Genes are mainly found in the clustered form in prokaryotes and known as operon.

II. Gene expression are regulated at the operon level in prokaryotes.

III. Operon genes are regulated by same regulatory region.

IV. This regulatory region have specific DNA subsequence known as promoter where RNA polymerase bind and start the transcription.

V. Transcription in prokaryotes is regulated by various transcription factors that are proteins required by RNA polymersae to bind efficiently.

VI. There are two main types of transcription factor thar regulate transcription . One is activator and other is repressor.

VII. Repressor suppress the transcription of gene whereas activator increase the rate of transcription

IX. Inducer is a specific molecule that either increase or decrease the rate of transcription in prokaryotes.

X. There are two main operons in prokaryotes, that are repressor operon include tryptophan and inducible operon include lactose.

XI. As, in prokaryotes, transcription and trsnslation occur simultaneously and in cytoplasm only,  there is no post transcription regulation in prokaryotes .