Eukaryotes, including animal and plant cells, are characterised by their membrane nucleus. They contain organelles such as mitochondria, which are located in the cytoplasm bound by membranes. Eukayotic cells divide by sexually and asexually, by meiosis or mitosis.
Prokaryotes, which include bacteria and cyanobacteria, don't have a membrane bound nucleus, their DNA exists as circular molecules in the cytoplasm. Prokaryotes divide asexually, usually by binary fission. Prokaryotes are smaller than eukaryotes, generally 1-10um, compared with 10-100um for eukaryotes.