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 genetic code consists of sequence of nucleotides containing the nitrogenous bases —A, C, G, U. These seuqences are present in an mRNA molecule. The nucleotides are combined in groups of three to form codons. The salient features of the genetic code are as follows:
- The codon is a triplet. 61 codons code for amino acids and 3 codons are stop codons.
- The start and stop codons, initiate and terminate the translation process respectively.
- AUG has dual functions. It codes for methionine (met), and it also acts as initiator codon.
- The codon is read in mRNA in a contiguous fashion. There are no punctuations.
- Unambiguous and specific - One codon codes for only one amino acid.
- Degenerate - amino acids are coded by more than one codon.-i.e., a given amino acid can be specified by more than one codon.
- Universal - for example, from bacteria to human UUU would code for Phenylalanine (phe).