A considerable amount of lactose is added to the growth medium of E.coli. How is the lac operon switched on in the bacteria.? Mention the state of the operon when lactose is digested.

Explanation

### Step-by-Step Solution:

1. **Understanding the Lac Operon Structure**: The lac operon consists of functional genes (I, P, O) and structural genes (Z, Y, A). The functional genes regulate the expression of the structural genes that code for enzymes needed to metabolize lactose.

2. **Role of the Repressor (I Gene)**: The I gene produces a repressor protein that binds to the operator (O) region of the lac operon. When the repressor is bound to the operator, it prevents RNA polymerase from transcribing the structural genes, thereby inhibiting the production of enzymes required for lactose digestion.

3. **Introduction of Lactose**: When lactose is added to the growth medium, it serves as an inducer. Lactose molecules bind to the repressor protein produced by the I gene.

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