How does mutation affect transcription?

Hint: Mutation is termed as the sudden and heritable change independent of the environment and it is able to provide a permanent step of which evolutionary changes may be built. These mutations can take place either in genes or chromosomes.

Complete answer:
The changes that can cause deformation in the chemical structure of the gene at the molecular level are called gene mutations or point mutations. Gene mutations can take place at the time of replication of DNA and therefore is also termed as the copy-error mutation. There are many steps that are present in replication, transcription and translation.
An alteration can take place in nitrogen bases at the third position of a codon may make the same sense when it does not lead to 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 lead to any change in the expression of the gene is called silent mutation.
Mis-sense mutation- It is termed as the one that constitutes change in a codon that generates a different amino acid at the specific site in polypeptide often resulting in the non-functioning.

A same-sense mutation is termed as a silent mutation in which the codon is changed but the change does not change the amino acid specificity.
A nonsense mutation is termed as the one that stops the polypeptide synthesis as the reason to the formation of a terminating or non-sense codon, i.e. ATT (UAA), ATC
(UAG), ACT (UGA).

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