Why are mistakes in transcription or translation not as serious as mutations in a gene?

Answer AND Explanation:

Mutation is a spontaneous change in the DNA. Gene mutation refers to changes in the nucleotide sequence in a particular gene while chromosomal mutation are changes in the gross structure of chromosomes.

During transcription or translation, RNAs are formed which are not heritable. Many copies of RNA are produced and a single bad one is not a big problem to the organism. Mismatch repair enzymes can fix any errors that were missed by the polymerases during transcription.