Question

Match column I with column II and select the correct option from the given codes.

	Column I		Column II
A.	Operator site	(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

• 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 1

Answer: (B)

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

The accessibility of promoter regions of prokaryotic DNA is regulated by interaction of proteins with sequences called as operators. Repressor molecules that repress gene expression bind to the operator sits and as a result the promoter cannot initiate gene transcription. Promoter is the site for the binding of the RNA polymerase to initiate the process of transcription. It refers to a conserved sequence that is specific for the binding of the RNA polymerase that can bring the expression genes for various functions.Regulator gene is the gene of an operon that codes for a repressor molecule that can bind to the operator sequence and stop gene expression. Structural gene codes for proteins or enzymes that are essential for the cell growth and survival

So, the correct option is 'A - (ii), B - (i), C - (iv), D - (iii)'.