In the lac operon, the repressor:a. binds to allolactose and becomes active, blocking lac gene expression. b. binds allolactose and binds to the promoter, and induces lac gene expression. c. binds to allolactose and becomes inactive, allowing lac gene expression to occur. d. binds to the promoter and blocks lac gene expression.

c. binds to allolactose and becomes inactive, allowing lac gene expression to occur.

Explanation:

Interaction between allolactose and repressor leads to allosteric repulsion which makes repressor inactive leading to the lac gene expression. This is the reason why allolactose is known as the inducer of lac operon becasue it causes gene expression in lac operon.

In the absence of allolactose, the repressor binds the operator and does not allow RNA polymerase to do transcription.

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure