Question

What is the function of a nonsense codon?
A.To release polypeptide chain from tRNA
B.To form an unspecified amino acid
C.To terminate the message of a gene controlled protein synthesis
D.To convert a sense DNA into non-sense DNA

Answer 1

Hint: Codons are a set of three nucleotides of DNA or RNA that specifically codes for a particular amino acid forming proteins by the translation process. These codons can code for 20 amino acids. The nucleotides are the nitrogenous bases which are attached to a sugar molecule along with phosphate groups. There are five types of nucleotides- adenine (A), thymine (T), guanine (G), cytosine (C) and uracil (U). The mRNA consists of the start codon, stop codon, the coding region (sense codons) and untranslated regions.

Complete answer:
Option A- To release polypeptide chain from tRNA
The release factors present in the polypeptide chain causes the detachment of the chain from tRNA, thus releasing the polypeptide chain.
Option B- To form an unspecified amino acid
The mutation which is caused due to insertion or deletion of nucleotide bases wrongly known as frameshift mutation. This leads to the formation of the wrong amino acids in the chain.
Option C- To terminate the message of a gene controlled protein synthesis
Stop codons also known as nonsense codons which causes the termination of the translation process. Such codons are UAG, UGA and UAA which code for the message to terminate the process.
Option D- To convert a sense DNA into nonsense DNA
During the transcription process, the DNA strands are uncoiled and transcribed into RNA. The strand used as a template in the process is called sense DNA and the other is called nonsense DNA.

Hence the correct answer is OPTION(C)

Note: Nucleotides A, G, C and T are found in DNA while A, G, C and U are found in RNA. These nucleotides form the genetic material in all living beings. There are 64 different codons. The start codon is AUG which starts the translation process. The codons are read from 5’ (N-terminal) to 3’ (C-terminal). Some of the amino acids coded are arginine, alanine, leucine etc.