Question

its not uninducible. pleae give explaination of what this process is ans how you got answer

"If the regulator protein of the arginine regulon is mutated such that it can not bind arginine, which of the following describes the phenotype of the bacterium with such a mutation?" inducible O repressible uninducible constitutive none of these

Answer 1

Answer: Arginine operon is a repressible operon. In this operon, arginine acts as co-repressor to the regulatory protein. When the concentration of arginine is high in the cell, arginine binds to regulatory protein and activates it. Activated regulatory protein binds to operator and inhibits the RNA polymerase enzyme to transcribe genes in the arginine operon. When arginine is low in the cell, arginine will not bind to regulatory protein. Inactive regulatory will not bind to operator and hence RNA polymerase enzyme transcribes the genes in the arginine operon.

When regulatory protein is mutated, it no longer binds to arginine and remains inactive. The inactive protein cannot bind to the operator and cannot inhibit the RNA polymerase. So, the genes will transcribe continuously. Hence, the phenotype of the bacterium with such a mutation is constitutive (continuous gene expression). The answer is option 4, Constitutive.