A bacterial colony consists of multiple microorganisms that are all from one mother cell, and they gather together and are genetically identical. This type of colony generally occurs as a result of the bacteria getting stronger defensively or mutating to survive antibiotics.
Bacteria only have one cell, making them unicellular organisms, and they are highly primitive. About 3.5 million years ago, bacteria occurred and they are now the most widely spread and numerous organisms on planet Earth. They contain one circular chromosome, a cell wall with peptidoglycan, and a cell membrane. They have no nuclear membrane, which makes them prokaryotic cells.