Question

What is genetic code? Write its four salient features. Draw a diagram of t-RNA.

Answer 1

The relationship between the nucleotide triplets and the amino acids is called a genetic code. This determines the sequence of amino acids in the proteins that are synthesized.

Salient features of genetic code are:

(i) The codon is triplet. 61 codons code for 20 amino acids and 3 codons do not code for any amino acids, hence they function as stop codons.

(ii) One codon codes for only one amino acid, hence, it is unambiguous and specific.

(iii) The code is degenerate because some amino acids are coded by more than one codon.

(iv)The codon is read in mRNA in a contiguous fashion. There are no punctuations.

(v)The code is nearly universal.

(vi) AUG codes for Methionine (met) and it also act as initiator codon.