Question

the processes of translation is a complex mechanism by which proteins are synthesized at the ribosome. a model of the process is shown here. examine the model and select all the choices below that are accurate in their description and their sequencing of the process of translation. a a trna molecule containing an amino acid enters the ribosome at the p site. b the elongating polypeptide/protein is synthesized at the p site of the ribosome. c the mrna is read three bases at a time which corresponds to a particular amino acid. d a trna molecule containing an amino acid enters the ribosome at the a site before moving to the p site. e trna molecules are reconnected with an amino acid before exiting the ribosome so the process can (continue)

Explanation:

• Option A: Incorrect. New aminoacyl-tRNAs enter at the A site, not the P site (the P site holds the growing polypeptide).
• Option B: Correct. The P site is where the elongating polypeptide chain is synthesized as peptide bonds form between amino acids.
• Option C: Correct. mRNA is read in codons (3-base units), each corresponding to one amino acid (or a stop signal).
• Option D: Correct. Aminoacyl-tRNAs first bind to the A site, then shift to the P site during ribosome translocation.
• Option E: (Text incomplete, but based on standard translation: tRNAs are recharged with amino acids after exiting, not before. So likely incorrect if the full text states "before exiting".)

Only B, C, D are accurate in description and sequencing.

Answer:

B. The elongating polypeptide/protein is synthesized at the P site of the ribosome, C. The mRNA is read three bases at a time which corresponds to a particular amino acid, D. A tRNA molecule containing an amino acid enters the ribosome at the A site before moving to the P site.