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

Which molecule carries genetic information from the nucleus to sites of protein synthesis?

1. tRNA

2. rRNA

3. mRNA

4. DNA

The correct answer is: mRNA

The molecule that carries genetic information from the nucleus to the sites of protein synthesis is messenger RNA, or mRNA. During the process of transcription, DNA is used as a template to synthesize mRNA in the nucleus. This mRNA molecule then travels out of the nucleus and into the cytoplasm, where it serves as a template for translation. In translation, ribosomes read the sequence of codons on the mRNA to assemble amino acids into a polypeptide chain, ultimately forming a protein. This function of mRNA is crucial because it acts as the intermediary that conveys genetic instructions from DNA, which is located in the nucleus, to the ribosomes, the cellular machinery responsible for protein synthesis. Other types of RNA, such as tRNA (transfer RNA) and rRNA (ribosomal RNA), play supportive roles in protein synthesis, but they do not carry genetic information from the nucleus. tRNA is responsible for bringing the appropriate amino acids to the ribosome based on the mRNA sequence, and rRNA forms the structural and catalytic components of ribosomes. DNA, while it holds the overall genetic information, remains in the nucleus and does not directly participate in the synthesis of proteins in the cytoplasm.