Question

Genetic code is unambiguous and specific. Explain?

Answer 1

Hint: The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequence) is translated in proteins in the living cells. Here unambiguous means one codon codes for only single amino acids and are specific.

Complete answer:
The genetic code is expressed in the linear form. It uses ‘letters’ the ribonucleotide base that compose RNA molecules. The ribonucleotide sequence is derived from the complementary nucleotide bases in DNA.

Each ‘word’ within the mRNA consists of three ribonucleotide letters is known as triplet code. The genetic code is unambiguous because each triplet specifies only a single amino acid.

The genetic code is non-overlapping. In translation, any single ribonucleotide within the mRNA is part of only one triplet. The code is universal but in viruses, prokaryotes, archaea and eukaryotes a single coding dictionary is used. mRNA serves as an intermediate in the transfer of genetic information from DNA to proteins.

Genetic code is an inter-relationship between nucleotides sequence of DNA or mRNA and amino acids sequence in a polypeptide chain. It is a mRNA sequence containing coded information for one amino acid and consists of 3 nucleotides.

Genetic code is unambiguous and specific in nature because one codon codes for only one amino acid. GUG is an ambiguous codon, it normally codes for valine but at initiating position it codes for methionine. AUG has dual functions, it codes for methionine but it also acts as an initiator codon.

Note: Each codon is independent and one codon does not overlap the next codon. Each codon is made up of three adjacent nitrogen bases. 61 codons code for amino acids. Codon in mRNA is read in a non-contiguous fashion.