Operon Concept

A gene product is a section of DNA that contains adjacent genes such as structural genes, operator genes, and regulatory genes. As a result, an operon is a primary component of translation and genetic regulation.

An Operon concept is a group of operationally associated genes dominated by a centralized controller. Operons are made up of many different genes that a producer and an operator connect. Operons exist in prokaryotes (bacteria and archaea) but not in eukaryotes. Multiple operons can be governed by many of the same transcription factors; in some cases, the operons establish a regulon.

Operon Structure

Operons are DNA regions that encompass groups of similar genes. They consist of a gene promoter region, an operator, and several related genes. The operator can reside inside the organizer and between the promoter and the genes. By connecting to the promoter region, RNA polymerase initiates transcription. The operator’s position is critical because its regulation either enables or hinders gene transcription into mRNA.

Function of Operon

An operon concept is applicable for a total package for the expression of genes and polypeptide synthesis. All polypeptides needed for a specific feature are produced in response to a specific stimulus by incorporating the associated genes. The bacterium Escherichia coli, for example, contains several genes arranged into operons and regulons:

• The Lac operon is implicated in lactose degradation.
• The Trp operon is implicated in tryptophan biosynthesis.
• His operon is implicated in histidine biosynthesis.

When the gene’s encoding is required, these operons are activated.

Prokaryotic Gene Regulation

The most comprehensive gene control in prokaryotes can be seen at the beginning of transcription. Thus, regulation impacts gene expression all through gene transcription. Typically, regulation occurs during the interpretation of the RNA polymerase at the promoter location. This has an influence on the accessory proteins that bind to the recognition sequence. These accessory proteins can control the promoter site in two ways:

• Activators exert positive control.
• Repressors exert negative control.

The operator in Operons is located right beside the promoter, where the regulator unites to rule the entire operation.

Concept of the Operon 

The operon model can describe the regulation of gene expression in prokaryotes. Changes in biological and developmental conditions can be observed here, resulting in changes in prokaryotic expression. The Operon is made up of the following components: 

Gene that regulates I: It encodes the repressor protein.

The z gene encodes beta-galactosidase, a protein that catalyzes the hydrolysis of lactose into glucose molecules.

y gene – This gene encodes permease, which governs lactose permeation in the cell.

a gene encodes transacetylase, an enzyme that assists the enzyme beta-galactosidase.

As a result, all of these genes contribute to lactose metabolism. Lactose acts as an activator in the Operon. When lactose is introduced to the bacteria’s medium, the regulatory gene is stimulated. The inducer will connect to the repressor protein and inactivate it, enabling transcription of the Operon to move ahead. In this case, the Operon is negatively regulated.

Eukaryotic Gene Regulation

Transcription factors, activators, and repressors regulate gene expression in eukaryotes. Repressors constrain transcription by connecting to specific DNA sequences. Transcription in eukaryotes consists of multiple phases. It can be found in both the nucleus (transcription) and the cytoplasm (translation).

Conclusion 

We discussed the Operon concept, what the operon concept is, what the operon concept is applicable for, and other related topics through the study material notes on the Operon concept. We also discussed Eukaryotic Gene Regulation & Prokaryotic Gene Regulation to give you proper knowledge.  

Genes involved in metabolism are found in Operon. The genes are only activated when present in excess, and glucose is not. The Operon is activated and deactivated in responding to the levels of glucose and lactose. These levels are catabolite activator protein and repressor.

 The repressor prevents the Operon from just being transcribed. It ceases to function as a repressor in the presence of lactose.

The catabolite activator protein activates the Operon’s transcription when glucose levels are low