Match the list of items Column I with Column II and select the correct option from the codes given below.
`{:("Column I", "Column II"), ("A. Operator side", "(i) Binding site for RNA polymerase"), ("B. Promoter site", "(ii) Binding site for repressor molecule"), ("C. Regulator gene", "(iii) Codes for protein/enzyme"), ("D. Structural gene", "(iv) Codes for repressor molecule"):}`

Options

A. A-(ii), B-(i), C-(iii), D-(iv)
B. A-(ii), B-(i), C-(iv), D-(iii)
C. A-(iv), B-(iii), C-(i), D-(ii)
D. A-(ii), B-(iii), C-(i), D-(iv)

Answer

To solve the matching question between Column I and Column II, we will analyze each item in Column I and find its corresponding match in Column II.

### Step-by-Step Solution:

1. **Identify the Operator Side:**
- The operator side is a region in an operon where a repressor molecule can bind. When the repressor binds to the operator, it prevents the transcription of the structural genes.
- **Match:** Operator side → (ii) Binding site for repressor molecule.

2. **Identify the Promoter Site:**
- The promoter site is where RNA polymerase binds to initiate transcription of the structural genes. It is essential for the transcription process to begin.
- **Match:** Promoter site → (i) Binding site for RNA polymerase.

3. **Identify the Regulator Gene:**
- The regulator gene codes for the repressor molecule that can bind to the operator. It plays a crucial role in regulating the operon by controlling the expression of the structural genes.
- **Match:** Regulator gene → (iv) Codes for repressor molecule.

4. **Identify the Structural Gene:**
- Structural genes are the segments of DNA that code for proteins or enzymes. In the case of the lac operon, these genes produce proteins necessary for the metabolism of lactose.
- **Match:** Structural gene → (iii) Codes for protein/enzyme.

### Final Matches:
- A. Operator side → (ii) Binding site for repressor molecule
- B. Promoter site → (i) Binding site for RNA polymerase
- C. Regulator gene → (iv) Codes for repressor molecule
- D. Structural gene → (iii) Codes for protein/enzyme

### Correct Option:
Based on the matches, the correct option is **B**.

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