A (aminoacyl) site

Definition

The A (aminoacyl) site on the ribosome is where the incoming aminoacyl-tRNA binds during protein synthesis. It plays a crucial role in translating mRNA into proteins by ensuring that the correct tRNA and its attached amino acid are added to the growing polypeptide chain.

5 Must Know Facts For Your Next Test

1. Located on the ribosome, specifically within the large subunit.
2. The A site is one of three key sites on the ribosome, along with the P (peptidyl) site and E (exit) site.
3. tRNA molecules carrying amino acids enter the ribosome at the A site.
4. The codon-anticodon interaction occurs at this site, ensuring proper amino acid addition based on mRNA sequence.
5. GTP hydrolysis provides energy for tRNA binding to the A site.

Review Questions

• What function does the A (aminoacyl) site serve in protein synthesis?
• How does tRNA interact with the A site on the ribosome?
• What ensures that the correct amino acid is added at the A site?

Related terms

P Site: The peptidyl-tRNA binding site where peptide bond formation occurs.

E Site: The exit site where deacylated tRNAs leave the ribosome.

Codon-Anticodon Interaction: Base pairing between mRNA codon and tRNA anticodon that ensures correct amino acid incorporation.