Bacteria

Bacteria are microscopic, single-celled organisms that exhibit a wide variety of shapes, metabolic types, and environmental adaptations. As prokaryotes, bacteria lack a nucleus; instead, their genetic material floats freely within the cell in a twisted, thread-like structure called the nucleoid. Some bacteria also possess plasmids, which are additional circular pieces of genetic material. Bacteria are generally only a few micrometers in length. Bacterial cells are enclosed by several protective layers around the cytoplasm: the capsule, cell wall and plasma membrane. The capsule, the outermost layer, is followed by the cell wall, which provides protection against osmotic stress and physical damage. Innermost is the plasma membrane, which regulates the transport of substances between the cytoplasm and the cell’s exterior. Within the cytoplasm, ribosomes play a crucial role in protein synthesis. Some bacteria are motile, possessing a flagellum that enables movement, allowing them to seek out new resources for survival. Additionally, many bacterial cells have short, thin, hair-like projections known as pili, which are used to attach themselves to surfaces, aiding in colonization and stability within their environment.