What is bacteria ? Definition, Sizes, Shapes, and Arrangements of Bacteria


Bacteria are neither plants nor animals they are of a large group of unicellular microorganisms (single-celled microorganisms) that consists of only one cell, they carry out all life processes as a single cell. Identifying of bacteria can be difficult Bacteria are found everywhere, bacteria can be found in the water, on the Plant or on the vegetable , on the body of animals, soil, on the surface of earth, inside the earth even on our

Shape of bacteria. 

There numerous of species of bacteria, but three basic shapes of bacteria. Bacteria can be determined primarily by three basic shapes: Bacillus, Coccus , and Spiralla

Rod-shaped Bactria is called bacillus. Sphere-shaped is coccus. Some are spiral or sphere known as spirilla 

Arrangement of Bacterial Cells

 Most of bacilli arranged in pairs called Diplobacilli.

 Some bacilli arranged in chains called Streptobacillus.

 Some bacilli are very short and fat rods these are called Coccobacilli.

 Cocci that arrange in pairs called diplococci.

 Some Cocci arranged in chains are called streptococci.

 Cocci that in two planes and arrange in groups of four cocci are called tetrads.

 Some cocci arrange in grape like clusters or sheets are called staphylococci.

 corynebacterium diphtheriae arranged in chinese latter pattern or v-latter pattern,

 haemophilus ducreyi seen in school of fish appearance.

 Vibrios like curved rods.

Spirilla have a helical shape.

 Spirochetes is spiral-shaped bacteria

Author: Dr. vivek saini


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