Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Ribosomes link amino acids together to form polypeptide chains according to instructions from what?

1. The RNA

2. The mRNA

3. The DNA

4. The tRNA

The correct answer is: The mRNA

The correct answer is that ribosomes link amino acids to form polypeptide chains according to the instructions provided by mRNA, or messenger RNA. During the process of protein synthesis, mRNA acts as a template that carries the genetic information transcribed from DNA. In the ribosome, the sequence of nucleotides in mRNA is translated into a specific sequence of amino acids, which are the building blocks of proteins. Each group of three nucleotides, called a codon, on the mRNA corresponds to a specific amino acid found in the polypeptide chain. While DNA contains the overall genetic information for constructing RNA, it is mRNA specifically that serves as the intermediary during translation. The tRNA (transfer RNA) plays a vital role by bringing the appropriate amino acids to the ribosome, matching them to the codons on the mRNA, but it is the mRNA itself that provides the direct instructions for peptide synthesis. Thus, mRNA is the critical molecule that ribosomes rely upon to assemble polypeptides, making it the correct choice in this context.