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Q.
The sequence of structural genes in lac operon is
Molecular Basis of Inheritance
Solution:
The lac operon consists of three structural genes ($lac Z, lac X lac A$). $Lac Z$ codes for $\beta$ -galactosidase which hydrolyses lactose to glucose and galactose. $Lac Y$ codes for lac permease, a membrane-bound protein constituent of the lactose transport system which increase permeability of the cell to $\beta$-galactosides. $Lac A$ codes of thiogalactoside transacetylase, an enzyme of uncertain metabolic function.