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: -Transcription does not have a start codon. The start codon is related to the process of translation in which the messenger RNA produced by transcription is used to make proteins. Transcription start sites can have any sequence. Codons are three base sequences which can specify an amino acid.

Detailed explanation-3: -The antisense or template strand of DNA acts as a template to transcribe mRNA. The ribosome reads the mRNA in three nucleotide codons, beginning with the start codon, AUG, which codes for the amino acid methionine.

Detailed explanation-4: -Usually, the first AUG in the mRNA is the point at which translation starts, and an open reading frame follows-i.e. the nucleotides taken three at a time will code for the Amino acids of the protein, and a stop codon will be found only when the protein coding region is complete.

Detailed explanation-5: -The codon AUG both codes for methionine and serves as an initiation site: the first AUG in an mRNA’s coding region is where translation into protein begins.