Final answer:
The true statement about each aminoacyl tRNA that enters the ribosome is that it carries an amino acid to be added to the growing polypeptide chain. The tRNA carries the correct amino acid as per the mRNA's codons and aids in the protein synthesis process by elongating the polypeptide chain.
Step-by-step explanation:
The statement that is true for each aminoacyl tRNA that enters the ribosome during protein synthesis is that it carries an amino acid to be added to the growing polypeptide chain. A tRNA molecule is designed to transport a specific amino acid to the ribosome, where protein synthesis occurs. At one end, the tRNA has an anticodon that is complimentary to the mRNA codon, ensuring that it brings the correct amino acid.
It is at the large ribosomal subunit that the amino acids are linked together. Peptidyl transferase, an important enzyme found in the ribosome, catalyzes the formation of peptide bonds between amino acids, elongating the polypeptide chain. Therefore, while tRNA does interact with mRNA through codon-anticodon pairing, and does bind to the ribosome, its specific function as it enters the ribosome is to carry an amino acid that gets added to the polypeptide chain being synthesized.