Regulation of Gene Expression

List the changes that the primary transcript undergoes to become functional mRNA.

A low level of expression of lac operon occurs at all the time. Justify the statement.

Distinguish between structural gene, regulatory gene and operator gene.

The image below shows the result of plating bacteria in a chromogenic medium after incorporating the gene of interest in the plasmid. Some plates had blue colonies; some plates had white colonies. A single bacterium extracted from Plate I, II, and III is shown below:

On the basis of your observations:

1. Identify the plate(s) which is/are white. Give a reason.
2. Identify the plate(s) which is/are blue. Give a reason.

Which of the following statements is correct about the role of regulatory proteins in transcription in prokaryotes?

When lactose is present in the culture medium:

In E.coli, three enzymes β- galactosidase, permease and transacetylase are produced in the presence of lactose. Explain why the enzymes are not synthesized in the absence of lactose.

Sometimes cattle or even human beings give birth to their young ones that are having extremely different sets of organs like limbs/position of eye(s) etc. Comment.