What is the function of ribosomes in a cell?

Ribosomes play a crucial role in the process of protein synthesis, which is fundamental to cell function and life itself. They serve as the cellular machinery where amino acids are assembled into proteins based on the instructions encoded in messenger RNA (mRNA). During translation, ribosomes read the sequence of the mRNA and facilitate the binding of transfer RNA (tRNA) molecules that bring specific amino acids to the growing polypeptide chain. This process is essential for creating proteins that perform a wide variety of functions in the cell, including structural support, transport, catalysis of biochemical reactions, and regulation of cellular processes.

The other options reference functions that are incorrect for ribosomes: DNA replication is primarily the role of various enzymes such as DNA polymerase; lipid production occurs in the smooth endoplasmic reticulum; and energy conversion is primarily associated with mitochondria in cellular respiration to produce ATP. Thus, ribosomes are uniquely specialized for their role in protein synthesis, making this answer the correct choice.