Kaplan Nursing Entrance Practice Exam

What process do ribosomes facilitate in cells?

1. DNA replication

2. Protein synthesis

3. Cell division

4. Metabolic breakdown

The correct answer is: Protein synthesis

Ribosomes play a critical role in the process of protein synthesis, also known as translation. During this process, ribosomes read the messenger RNA (mRNA) sequences that have been transcribed from DNA. They use the information carried by the mRNA to assemble amino acids into polypeptide chains, which then fold into functional proteins. This is essential for a wide range of cellular functions, as proteins are the building blocks of cells and the primary agents of biological activity. The ribosomal activity occurs in two main stages: initiation, where the ribosome assembles around the mRNA and the first transfer RNA (tRNA), which carries the amino acid; elongation, where additional tRNAs bring new amino acids to the growing polypeptide chain as the ribosome moves along the mRNA; and termination, when the ribosome encounters a stop codon and releases the completed protein. None of the other options represent the primary function of ribosomes. DNA replication occurs in the nucleus and involves DNA polymerase enzymes, while cell division is a complex process involving mitosis or meiosis that does not involve ribosomes directly. Metabolic breakdown encompasses various biochemical reactions that break down molecules for energy, which also does not involve ribosomal activity. Hence,