Question

Match the gene in Column I with its role in Column II.

Column I (Gene)	Column II (Role of gene)
(A) Structural gene	(I) Binding site for repressor
(B) Operator gene	(II) Codes for repressor
(C) Promoter gene	(III) Codes for enzyme
(D) Regulator gene	(IV) Binding site for RNA polymerase

Choose the correct option.

• A. A-II, B-III, C-I, D-IV
• B. A-III, B-I, C-II, D-IV
• C. A-III, B-IV, C-I, D-II
• D. A-III, B-I, C-IV, D-II

Hint:

Recall what the structural, operator, promoter and regulator genes of the lac operon do.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
The lac operon has a regulator gene, a promoter, an operator and structural genes, each with a distinct role.

Step 2: Match the genes
Structural gene codes for the enzymes (III).
Operator is the binding site for the repressor (I).
Promoter is the binding site for RNA polymerase (IV).
Regulator gene codes for the repressor (II).

Step 3: Write the pairs
A-III, B-I, C-IV, D-II.

Final Answer:
The correct matching is A-III, B-I, C-IV, D-II. \[ \boxed{\text{(D) }\text{A-III, B-I, C-IV, D-II}} \]