Which of the following structures is not found in a prokaryotic cell?

Nuclear membrane is not found in a prokaryotic cell. Prokaryotes lack true nucleus and the genetic material lies naked in the cytoplasm. Mesosomes are invaginations of the plasma membrane that are found mostly in gram positive bacteria. Plasma membrane is a structure that is present both in eukaryotes as well as prokaryotes.70S ribosome will be present in prokaryotes, mitochondria, and plastids.