Final answer:
The ribosome is the only cell organelle among the given options that does not have a membrane, distinguishing it from the smooth ER, rough ER, lysosome, and Golgi complex.
Step-by-step explanation:
Of the given options, Ribosome is the cell organelle that does not possess a membrane. Among the listed cell organelles, the ribosome is the one that does not possess a membrane of some type. Cell organelles such as the smooth endoplasmic reticulum (SER), rough endoplasmic reticulum (RER), lysosome, and Golgi complex are all membrane-bound, involved in various cellular processes. The ribosome, however, is not bounded by a membrane and is the site of protein synthesis in both eukaryotic and prokaryotic cells. It is made up of two ribosomal RNA subunits that facilitate the translation of mRNA into protein.