Members of Monera, which include the prokaryotic bacteria and cyanobacteria, are single-celled and lack a membrane-bound nucleus. They also lack other membrane-bound organelles, such as mitochondria, and reproduce asexually.
Members of Monera can be contrasted sharply with eukaryotic organisms because many of their characteristics are completely opposite. Eukaryotes can be single or multicellular and do have a membrane bound nucleus. Other organelles, such as the mitochondria and chloroplasts, are also membrane bound. In the five kingdom classification system, Monera is the only kingdom that is comprised of prokaryotes. All other kingdoms of Protista, Plantae, Fungi and Animalia contain organisms that are eukaryotic.