AP BIOLOGY

Detailed explanation-1: -The standard start codon for translation of a gene is “AUG, ” which encodes the amino acid methionine (Met or M), and establishes the reading frame for the ribosome to follow, adding corresponding amino acids in a polypeptide chain.

Detailed explanation-2: -AUG is the most common START codon and it codes for the amino acid methionine (Met) in eukaryotes and formyl methionine (fMet) in prokaryotes. During protein synthesis, the tRNA recognizes the START codon AUG with the help of some initiation factors and starts translation of mRNA.

Detailed explanation-3: -The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and Archaea and a N-formylmethionine (fMet) in bacteria, mitochondria and plastids.

Detailed explanation-4: -Although methionine (Met) is the first amino acid incorporated into any new protein, it is not always the first amino acid in mature proteins-in many proteins, methionine is removed after translation.