Bacteria are unicellular prokaryotic microorganisms. They do not have nuclear membrane. The nucleus consists of double-stranded circular DNA. They possess long filamentous flagella protruding through cell wall which is used for locomotion. They also contain thin, short filaments called as fimbriae or pili. Some bacteria posses capsule which is the outer covering of cell wall. It is mainly made up of polysaccharide. Cell wall is the rigid outer covering of the bacteria. It is made up of peptidoglycan. It gives a particular shape to bacteria. They do not contain nuclear membrane, golgi complex, cytoskeleton. They contain cytoplasmic membrane, mesosomes, ribosomes and cytoplasmic inclusions.