however, recent research has shown that at least some prokaryotes have [[bacterial microcompartment|microcompartment]]s such as [[carboxysome]]s. these subcellular compartments are 100–200 nm in diameter and are enclosed by a shell of proteins. even more striking is the description of membrane-bound magnetosomes in bacteria. as well as the nucleus-like structures of the "planctomycetes" that are surrounded by [[lipid bilayer|lipid membranes]].