Topic: Protein Synthesis (Translation)
Translation is the process of building a protein based on the genetic code in mRNA. Every protein starts with a specific "start" signal.
Steps:
Understanding the Question: What is the very first amino acid placed in a growing protein chain in eukaryotic organisms?
Key Formulas and Approach: The universal start codon on mRNA is AUG. This codon specifies one particular amino acid.
Detailed Solution:
In eukaryotes, the ribosome searches for the start codon, which is always AUG.
The initiator tRNA brings the amino acid Methionine to match this AUG codon.
Therefore, almost all eukaryotic proteins begin with Methionine (though it may be removed later after the protein is finished).
(Note: In prokaryotes, the initiator is a slightly modified version called N-formylmethionine).