The human diseases, tuberculosis and leprosy, are caused by members of this group. Protein synthesis occurs there in eucaryotes, but not in procaryotes. They control chemotaxis in bacteria. The endospores of Bacillus anthracis are the biological weapon of choice because this species of endospore forming bacteria is aerobic and produces a deadly toxin in its vegetative cycle. The endospores of Clostridium botulinum are killed by contact with oxygen so they are only found in anaerobic sites such as deep in the ocean.
Endospores are an alternative reproductive method to binary fission.
Must include a crystalline protein coat composed of capsomeres forming a helical or isocohedral structure. May have an outer covering over the capsid made of host cell membrane. May have an outer covering over the envelope called a glycocalyx made of polysacchride. May have attached projecting appendages in the form of flagella, fimbriae, pili or spikes. Specialized membrane bound vacuoles are essential for a cell to store nutrients in the cytoplasm.