Question

Explain why (b) Inactivation of both O₂ and O₃reduces repression – 70 fold.

Short answer

In the lac operon, only O₁is required for activation of repression O₂ and O₃inhibits repression.

Step-by-step solution

Activation of the lac operon

In lac operon only O₁ is required for activation of repression, can bind up with the operator gene and can encode the structure.If lac operon binds with an SO₃, it forms a loop of a₃ BP long. If lac operon binds with O₁ SO₂, it makes a loop of 401 BP long.

Repressor of the lac operon

The O₃ repressor has operator sites for binding O₂ and O₃. After binding it isa form of a loop.

Hence, reduces repression -70 fold during inactivation of both O₂ and O₃.