Question

What is not true for genetic code?

• A. It is unambiguous
• B. A codon in mRNA is read in a noncontiguous fashion
• C. It is nearly universal
• D. It is degenerate

Answer 1

The correct option is B A codon in mRNA is read in a noncontiguous fashion

The salient features of genetic code are as follows:
(i) The codon is a triplet. 61 codons code for 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) Some amino acids are coded by more than one codon, hence the code is degenerate.
(iv) The codon is read in mRNA in a contiguous fashion. There are no punctuations.
(v) The code is nearly universal: for example, from bacteria to human UUU would code for Phenylalanine (phe). Some exceptions to this
rule have been found in mitochondrial codons, and in some protozoans.
(vi) AUG has dual functions. It codes for Methionine (met), and it also acts as initiator codon.