Question

A nonsense mutation results into
A. Stoppage of transcription
B. Change in protein structure
C. Stoppage of protein synthesis
D. Termination of polypeptide chain

Answer 1

Hint:-Mutation is sudden and heritable change independent of the environment and liable to provide a permanent step of which evolutionary changes may be built. These mutations can occur either in genes or chromosomes.

Complete step-by-step solution:-The various types of mutations are:
The changes that alter the chemical structure of the gene at the molecular level are called gene mutations or point mutations. Gene mutations occur at the time of replication of DNA and therefore is also called copy-error mutation. There are many steps involved in replication, transcription and translation
A change in nitrogen bases at the third position of a codon may make the same sense when it does not cause any change in the expression of the codon because the codon is mostly read by the first two nitrogen bases. The mutation that does not cause any change in the expression of the gene is called silent mutation.
Mis-sense mutation- It is the one that involves change in a codon that produces a different amino acid at the specific site in polypeptide often resulting in the non-functioning.
A same-sense mutation is a silent mutation in which the codon is changed but the change does not alter the amino acid specificity.
A nonsense mutation is the one that stops the polypeptide synthesis due to the formation of a terminating or non-sense codon, i.e. ATT (UAA), ATC (UAG), ACT (UGA).

Correct option: D. Termination of polypeptide chain

Note:- Mutations may be spontaneous mutations that occur randomly, naturally and automatically due to internal reasons without any relation to any external factor or induced mutations that are produced in response to specific external factors and chemicals.