Monosomes

Monosomes are the fundamental units of protein synthesis in all living cells. They are complex molecular machines responsible for translating messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins. Each monosome consists of two major subunits: a small subunit and a large subunit. These subunits are composed of ribosomal RNA (rRNA) and ribosomal proteins. During protein synthesis, the small subunit binds to the mRNA molecule, while the large subunit catalyzes the formation of peptide bonds between amino acids, guided by the sequence of codons on the mRNA.

The structure of monosomes varies slightly between prokaryotes and eukaryotes. Prokaryotic monosomes are typically 70S in size, composed of a 30S small subunit and a 50S large subunit. Eukaryotic monosomes are larger, measuring 80S, with a 40S small subunit and a 60S large subunit. This difference in size is significant for drug development, as many antibiotics target the prokaryotic monosome without affecting the eukaryotic one. Monosomes are found freely in the cytoplasm or attached to the endoplasmic reticulum, depending on the destination of the protein being synthesized. The precise assembly and function of monosomes are crucial for cellular life.