Bacterial Cell Structure and Function (with Diagram)

In this article we will discuss about the bacterial cell structure and function.

Bacteria are unicellular prokaryotic microorganisms that divide via binary fission. They lack a nuclear membrane, and the nucleus consists of a single chromosome of cir­cular double-stranded DNA helix.

bacterial cell structure and function


These are long, filamentous, cytoplasmic appendages that protrude through the cell wall and contain the contractile protein flagellin. They range in length from 12 to 30 m. These are locomotor organs.


These are thin, short filaments (0.1-1.5 m x 4 to 8 nm) that protrude from the cytoplasmic membrane and are also known as pili. They are protein-based (pilin).


The cell wall is encased in a thin, jelly-like layer that has a thickness of 0.2 m. Only some types of bacteria have capsules. Typically, a capsule is formed of a polysaccharide (such as pneumococcus), a polypeptide (such as anthrax bacilli), and hyaluronic acid (e.g. streptococcus).

Cell wall

It is a strong, rigid structure of peptidoglycan that surrounds the bacterium like a shell and is located outside of the cytoplasmic membrane. It contains accessory specialised components. It has a thickness of 10–25 nm. It gives the cell form.


The bacterial genome is a single circular, double-stranded chromosome. Cytoplasmic membrane, mesosomes, ribosomes, and cytoplasmic inclusions are further structures. The cytoplasm of prokaryotes does not contain the ribosome, Golgi, or cytoskeleton.