A eukaryotic ribosome is a complex molecular machine found in the cells of eukaryotes, which include organisms like plants, animals, and fungi. It plays a crucial role in protein synthesis by translating messenger RNA (mRNA) into polypeptide chains. Eukaryotic ribosomes are larger than their prokaryotic counterparts, consisting of two subunits: a large subunit (60S) and a small subunit (40S), which together form an 80S ribosome. These ribosomes are primarily located in the cytoplasm and can also be found attached to the endoplasmic reticulum, forming rough ER. They are essential for cellular function, as proteins produced by ribosomes are vital for various biological processes, including metabolism, cell structure, and signaling.