Besides a nucleus, prokaryotes lack other things eukaryotes (cells with a true nucleus) have. They reproduce without fusion of gametes. They do not have membranes inside the cell. This means that there are no vacuoles, Golgi apparatus, endoplasmic reticula or other organelles inside the cell. However, they do have ribosomes, though of a simpler kind than eukaryotes. Eukaryote cells include organelles which were once free-living prokaryotes.