Question

Nonsense codon takes part in:
(A) Terminating message of gene-controlled protein synthesis.
(B) Formation of unspecified amino acids.
(C) Conversion of sense DNA into non-sense one.
(D) Releasing tRNA from polypeptide chain.

Answer 1

Hint: A DNA or RNA molecule that has a sequence of three sequential nucleotides that codes for a certain amino acid. Some codons act as start or stop signals for translation. Twenty amino acids are encoded by 64 codons.
Step by step solution:
A codon is a genetic sequence of three letters that can be found in both DNA and RNA.
It specifies a particular amino acid or provides start and stop commands for the production of proteins. Three consecutive nucleotides are specifically ordered in the genetic code to specify a particular amino acid in a protein or to initiate or terminate protein synthesis. A, C, T, and G are the four nucleotides that makeup DNA, whereas 20 amino acids are used to make proteins.
The sequence AUG, which designates the amino acid methionine, is an illustration of a codon. Every messenger RNA (mRNA) begins with the AUG codon, which not only codes for the amino acid methionine but also denotes the beginning of a protein.
Stop codons are also known as nonsense codons since they signify the end of protein synthesis rather than encoding an amino acid. So, prematurely introducing nonsense or stop codons into the DNA sequence results in nonsense mutations.
So, option (A) is correct.
Note: A codon that signifies the end of translation or punctuation but does not code for any amino acids. These are as follows: UAG (amber), UAA (ochre), and UAG are the three nonsense codons (opal).