Ribonucleoproteins (RNPs) are complex molecules made up of both RNA and proteins. They play essential roles in various cellular processes, including the synthesis of proteins and the regulation of gene expression. RNPs are found in all living cells and are crucial for the proper functioning of the cell's machinery. One well-known type of RNP is the ribosome, which is responsible for translating messenger RNA (mRNA) into proteins. Other examples include small nuclear ribonucleoproteins (snRNPs), which are involved in RNA splicing, and telomerase, an RNP that helps maintain the ends of chromosomes.