What is the function of ribosomes in the cell?

• A. Replication of DNA
• B. Sites of protein synthesis
• C. Energy production
• D. Storage of nutrients

Answer: (B)

Ribosomes play a crucial role in the cell as the sites of protein synthesis. They are complex molecular machines composed of ribosomal RNA (rRNA) and proteins, and their primary function is to translate messenger RNA (mRNA) sequences into amino acid chains, forming proteins. This process is known as translation and is essential for the expression of genes and the production of proteins that perform various functions within the cell, including structural roles, enzyme activities, and signaling pathways.

During translation, ribosomes read the mRNA, which provides the template for the protein being synthesized. Transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome, where they are sequentially added to the growing polypeptide chain based on the codon sequence of the mRNA. This ensures that proteins are synthesized accurately according to the genetic instructions.

The other options address different cellular functions: replication of DNA involves different cellular machinery, energy production is primarily associated with organelles like mitochondria, and the storage of nutrients is typically managed by structures such as vacuoles or specialized cells. Thus, ribosomes are specifically dedicated to the critical process of protein synthesis within the cell.