Structure of bacterial cell

Structure of bacterial cell is varying with the species of the bacteriae. But the basic structure is same for the all bacteriae. Therefore study of this common structure will enable the ability of understanding the varying configurations of structure.

Followings are the important structures/features found in almost all the bacterial cells.

1. shape and size of bacterial cell
2. cell wall of bacterial cell
3. cytoplasmic membrane of bacterial cell
4. mesosome of bacterial cell
5. cytoplasm of bacterial cell
6. specialized structures outside the cell wall of bacterial cell
7. spores of bacteriae


Shape and size of bacterial cell

There are three basic groups of bacteriae according to the shape of the cell.

1. Cocci (round shape)
2. Bacilli (rod shape)
3. Spirochetes (spiral shape)

Other than those basic shapes, there are some bacteriae who do not have a specific shape or shape is varying. Those bacteriae are known as pleormorphic.

Bacteria size could range from about 0.2µm to 5µm. This is general measurement therefore there can be bacteriae larger/smaller.

Cell wall of bacterial cell

This is the outermost part of bacterial cell of almost all the bacteriae. There are few groups who do not possess a cell wall such as mycoplasma. Various structures could be attached to the cell wall such as capsule, flagellae. The cell consists of several layers. Followings are the component of bacterial cell wall;

Peptidoglycan
Teichoic acid
Lipid A
Polysaccharides

Cytoplasmic membrane of bacterial cell

Cytoplasmic membrane is found inside to the cell wall. It is microscopically similar to cell membrane of eukaryotic cell but the chemical composition is different. Followings are the functions of cell membrane;

1. active transport of molecules
2. energy generation
3. synthesize of component of cell wall
4. secretion of enzymes and toxins

mesosome of bacterial cell

This is an invagination of the cell membrane and it is important for the cell division.

Cytoplasm of bacterial cell

All the organelles of the bacteriae are suspended in the cytoplasm. This is somewhat similar to cytoplasm of the eukaryotic cytoplasm but chemical composition is varying. Followings are the structures found in cytoplasm;

1. ribososmes
2. granules
3. nucleid
4. plasmids
5. transposons


Specialized structures outside the cell wall

Capsule
Flagella
Pili (fimbriae)
Glycocalyx

Spores of bacterial cell

This is not a common structure for all bacterial cells. This highly specialized structure is important to pass the difficult environmental conditions. Bacillus and clostridiums are the bacteriae which produce spores.