Question

Describe the structure of `Operon'.

Answer 1

Dear Student,

◆ Operon -

• Functioning unit of DNA containing a cluster of genes under the control of a single promoter is called operon.

● Lac operon -

• Lac operon codes for enzymes associated with degradation of lactose.
• Operon gets induced in presence of lactose and off in absence of lactose.

It codes for three genes -

(1) β-galactosidase -

• splits lactose into glucose and galactose.
• Encoded by gene LacZ.

(2) lactose permease -

• controls entry of glucose.
• Encoded by gene LacY.

(3) lactose transacetylase -

• transports acetyl group.
• Encoded by gene LacA.

Thanks dear...

Answer 2

Answer:

(1) An operon is a unit ot gene expression and regulation.

(2) It includes the structural genes and their control elements. Control elements are promoters and operators.

(3) The structural genes code for proteins, r-RNA and t-RNA that are necessary for all the cells

(4) Promoters are signal sequences in DNA. They start the RNA synthesis. They also act as sites where the RNA polynerases are bound during transcription.

(5) Operators are present between the promoters and structural genes.

(6) There is repressor protein that binds to the operator region or the operon.

(7) There are regulatory genes which are responsible for the formation of repressors which interact with operators.