Which of the following is not a ribosomal position used to add amino acids to a growing polypeptide chain?

• A. A site
• B. C site
• C. P site
• D. E site

Answer: (B)

Verified step by step guidance

1. Understand the function of ribosomal sites: The ribosome has specific sites where tRNA molecules bind during protein synthesis. These sites are crucial for the translation process.
2. Identify the A site: The A site (Aminoacyl site) is where the incoming aminoacyl-tRNA binds, bringing a new amino acid to be added to the growing polypeptide chain.
3. Identify the P site: The P site (Peptidyl site) holds the tRNA carrying the growing polypeptide chain. This is where peptide bonds are formed between amino acids.
4. Identify the E site: The E site (Exit site) is where the tRNA, after transferring its amino acid, exits the ribosome.
5. Recognize the C site: The C site is not a recognized ribosomal site involved in the process of translation. Therefore, it is not used to add amino acids to a growing polypeptide chain.