AP BIOLOGY

Detailed explanation-1: -The codon AUG is called the START codon as it the first codon in the transcribed mRNA that undergoes translation. AUG is the most common START codon and it codes for the amino acid methionine (Met) in eukaryotes and formyl methionine (fMet) in prokaryotes.

Detailed explanation-2: -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-3: -AUG codon codes for the methionine whereas GUG also functions as a start codon. These start codons always codes for the methionine and they are universal and codes for the same in both eukaryotes and prokaryotes. Hence, the correct answer is option (D).

Detailed explanation-4: -The rational design of theoretical minimal RNA rings predetermines AUG as the universal start codon. This design maximizes coded amino acid diversity over minimal sequence length, defining in silico theoretical minimal RNA rings, candidate ancestral genes.

Detailed explanation-5: -An example of a codon is the sequence AUG, which specifies the amino acid methionine. The AUG codon, in addition to coding for methionine, is found at the beginning of every messenger RNA (mRNA) and indicates the start of a protein.