Describe the common bacterial shapes and the fundamental characteristics all bacteria share.
There are three basic bacterial shapes: spherical, rod-shaped, and helically coiled. Spherical bacteria are known as cocci, rod-shaped as bacilli, and helical as spirilla. Some bacteria remain together after cell division forming a multicellular aggregate where consecutive cells share cell walls. Most bacteria have cell walls which not only protect them from physical damage but also from bursting since most bacteria are hypertonic relative to their surrounding environment. Additionally, most bacteria can secrete a capsule, consisting of mucoid materials, over their cell wall that makes them more resistant to a host's defenses.
