Bacterial cellular morphologies

Bacterial Cellular Morphologies

Bacterial cellular morphologies refer to the various shapes and structural forms of bacteria. Bacteria are single-celled microorganisms that come in a variety of shapes and sizes. The three most common shapes are coccus (spherical), bacillus (rod-shaped), and spirillum (spiral).

Coccus

Coccus bacteria are spherical in shape. They can exist as single cells or can group together in pairs (diplococci), chains (streptococci), or clusters (staphylococci). Examples of coccus bacteria include Staphylococcus aureus and Streptococcus pneumoniae.

Bacillus

Bacillus bacteria are rod-shaped. They can exist as single cells, in pairs (diplobacilli), or in chains (streptobacilli). Examples of bacillus bacteria include Escherichia coli and Bacillus anthracis.

Spirillum

Spirillum bacteria are spiral-shaped. They are usually found in stagnant water and in the human body. Examples of spirillum bacteria include Spirillum minus and Campylobacter jejuni.

Other Morphologies

In addition to the three most common shapes, bacteria can also take on other morphologies. For example, vibrio bacteria are comma-shaped, spirochete bacteria are long and tightly coiled, and pleomorphic bacteria can change their shape in response to their environment.

Importance of Bacterial Morphology

The shape of a bacterium can influence its pathogenicity, its ability to survive in different environments, and its mode of movement. For example, spiral-shaped bacteria can move more easily through viscous environments, such as mucus, than rod-shaped or spherical bacteria.

See Also

• Microbiology
• Bacteriology
• Cell biology