Question

AUG codon is an
A)Ochre
B)Amber
C)Initiation codon
D)Opal

Answer 1

Hint: The universal genetic code consists of multiple codons or triplet bases. There are a total of 64 codons in the genetic code resulting from the permutation and combination of the 4 bases in nucleic acids. The genetic code is degenerate, i.e. more than one codon can be coded for a single amino acid.

Complete answer:
There are two punctuation marks in the genetic code called START and STOP codons that signify the end of protein synthesis in all species. The genetic code can be read in several forms depending on where the reading begins. There are three ways to read the code of each strand of genetic material.

These various ways of reading a nucleotide sequence are known as a reading frame. Each reading frame can contain a different sequence of amino acids and therefore proteins. The code AUG is considered the START code as the first codon in the transcribed mRNA to be translated. AUG is the most common START codon and codes for amino acid methionine in eukaryotes and formylmethionine in prokaryotes. During protein synthesis, the tRNA recognizes the START codon AUG with the aid of certain initiation factors and begins the translation of the mRNA.

Hence, the correct answer is option (C)

Note: The genetic code has 3 STOP codons - UAG, UAA, and UGA. During translation, these codons signify the end of the polypeptide chain. These codons, although they do not code for an amino acid, are also known as nonsense codons or termination codons. The three STOP codons are known as amber (UAG), opal or umber (UGA) and ochre codons (UAA).