Final answer:
The first amino acid in a synthesized polypeptide is located at the N-terminal. The AUG codon initiates synthesis with methionine, which is sometimes removed during protein maturation.
Step-by-step explanation:
When a polypeptide is synthesized, the first amino acid to be put in place is located at the N-terminal.
The codon AUG is the initiation codon for protein synthesis, coding for the amino acid methionine. This means that methionine is commonly the starting amino acid in newly synthesized polypeptides.
However, this initial methionine is frequently removed enzymatically during later stages of protein processing, resulting in a mature polypeptide that doesn't begin with methionine.
Additionally, polypeptides are synthesized from the amino (N-) terminal to the carboxyl (C-) terminal end. Each polypeptide features a free amino group at the N-terminal and a free carboxyl group at the C-terminal. The sequence of amino acids in a polypeptide is traditionally written from N-terminus to C-terminus, indicating the direction of synthesis during protein translation.