Question

Which of the following does not play a role in the genetic regulation of tryptophan synthesis in the bacterium E.coli?
A. RNA polymerase
B. Homeotic gene
C. Repressor protein
D. Operator

Answer 1

Hint: Tryptophan (Trp) is an alpha-amino acid that is utilised in the biosynthesis of proteins. Tryptophan is a nonpolar aromatic amino acid with an alpha-amino group, an alpha-carboxylic acid group, and an indole side chain.

Complete Step by Step Answer:
To fulfill the metabolic requirements of the cells, bacteria must synthesise various enzymes. Such enzymes are proteins that are made up of amino acids. Bacterial cells must produce amino acids in order to synthesise these enzymes. Tryptophan is however one such amino acid synthesised by bacteria.
In E. coli, tryptophan synthesis is conducted by 5 different genes. All of these genes are controlled by one operator which regulates tryptophan synthesis. This operator activates tryptophan synthesis only if tryptophan levels in the system are low. But unless tryptophan levels are high, the operator turns off the tryptophan synthesis genes. An operon is formed whenever a single gene, for instance, the operator in this scenario, controls a group of genes in this manner. The tryptophan operon, also known as the Trp operon, controls tryptophan synthesis in E. coli.
TrpE, TrpD, TrpC, TrpB, and TrpA are the five structural genes. Each gene encodes the mRNA for the enzyme involved in the tryptophan synthesis pathway. There is a promoter area (P) that RNA polymerase could indeed bind to. When RNA polymerase binds to this area, it aids in the initiation of mRNA synthesis from structural genes. When the tryptophan level is high, an operator gene inhibits tryptophan synthesis. It accomplishes this by connecting to a repressor protein. Thus, the homeotic gene does not play a role in the genetic regulation of tryptophan synthesis in E. coli.

The correct option is B

Note: Homeotic genes are in the role of determining the authenticity of specific body segments or structures. As a consequence, when homeotic genes are inactivated or conveyed in unordinary regions as an outcome of mutations, body segments may take on unique and sometimes startling identities.