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Match List-I with List-II
Choose the correct answer from the options given below: |
(A)-(I), (B)-(II), (C)-(III), (D)-(IV) (A)-(I), (B)-(III), (C)-(II), (D)-(IV) (A)-(IV), (B)-(I), (C)-(II), (D)-(III) (A)-(III), (B)-(IV), (C)-(I), (D)-(II) |
(A)-(IV), (B)-(I), (C)-(II), (D)-(III) |
The correct answer is Option (3) → (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
The lac operon consists of one regulatory gene (the i gene – here the term i does not refer to inducer, rather it is derived from the word inhibitor) and three structural genes (z, y, and a). The i gene codes for the repressor of the lac operon. The z gene codes for beta-galactosidase ( β-gal), which is primarily responsible for the hydrolysis of the disaccharide, lactose into its monomeric units, galactose and glucose. The y gene codes for permease, which increases permeability of the cell to β-galactosides. The a gene encodes a transacetylase. Hence, all the three gene products in lac operon are required for metabolism of lactose Lactose is the substrate for the enzyme beta-galactosidase and it regulates switching on and off of the operon. Hence, it is termed as inducer. |
