question_answer

Lac operon is considered to be regulated by its substrate. Explain.

Or

Inheritance is particulate in nature. Why?

Answer:

Lac operon was the first operon discovered by Jacob and Monad (1961). It is regulated by its substrate (lactose) as the presence or absence of lactose regulates the activity of lac operon. When lactose is present it binds to the repressor protein of operon. This allows RNA polymerase to access to the promoter and transcription proceeds. In the absence of lactose the repressor binds to operator and prevents RNA polymerase from transcribing the operon.

Or

The parents contain two alleles during gamete formation, the factors or alleles of a pair segregate from each other, such that a gamete receives only one of the two factors.

The alleles do not show any blending and both characters are recovered as such in \[{{F}_{2}}\]-generation, though one of there is not seen in \[{{F}_{1}}\]-generation.