The United Illuminating Company (UI) is a regional electric distribution company based in Orange, Connecticut.
Although generally not visible to the naked eye, organisms composed of prokaryotic cells still dominate the earth. Their collective mass is at least 10 times greater than the mass of all eukaryotes combined. Organisms composed of prokaryotic cells are classified into 2 main groups: archaea and bacteria. Archaea most closely resemble the first primitive cells on our planet.
There are two primary types of cells: eukaryotic cells and prokaryotic cells. Eukaryotic cells are called so because they have a true nucleus. The nucleus, which houses DNA, is contained within a membrane and separated from other cellular structures. Prokaryotic cells however have no true nucleus. DNA in a prokaryotic cell is not separated from the rest of the cell but coiled up in a region called the nucleoid. As organized in the Three Domain System, prokaryotes include archaeans and bacteria. Eukaryotes include animals, plants, fungi and protists.