Short rods termed coccobacilli usually come in single arrangement. Bacteria can be partially characterized but not classified by their morphology. Very specific metabolic tests are used to identify individual species. Round bacteria or cocci exist in many arrangements. Simple stains such as crystal violet and lactofuchsin are used to give definition to bacteria whereas differential stains are needed to see capsules and some spores.
Bacteria have varied metabolic capabilities.
Some are strictly aerobic or anaerobic while others are facultative anaerobes. Most use preformed organic molecules for carbon and energy while others use inorganic C02 for carbon and light or inorganic molecules for energy. Yet others use organic carbon as carbon source and inorganic molecules for energy. Some bacteria produce endospores. This is a specialized structure which gives the cell resistance to environmental stresses.