Allolactose, an isomer of lactose, is formed in small amounts from lactose. an e. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. which of the following occurs when lactose enters the cell? allolactose, an isomer of lactose, is formed in small amounts from lactose. an e. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source.
which of the following occurs when lactose enters the cell?

a. allolactose binds to the regulator gene.
b. allolactose binds to the repressor protein.
c. rna polymerase attaches to the regulator.
d. the repressor protein attaches to the regulator.
e. the repressor protein and allolactose bind to rna polymerase.