![]() ![]() Cell multiplication occurs in one plane.Įxamples: Streptococcus pyogenes, Streptococcus mutans, Streptococcus mitis etc. ![]() Streptococci: They form a chain by adhering to each other.Diplococci: These cells appear in pairs, and the cell division occurs in one plane.Įxamples: Neisseria gonorrhoea, Diplococcus pneumoniae etc. ![]() They exist in various forms based on the arrangement and cell number: In cocci, cell division can occur in many ways like in one plane, two planes, three planes or randomly. Cocci cells can remain attached after the cell division. The arrangement of cocci is more complicated than the bacilli. The bacteria are grouped into four types based on bacterial cell arrangement and cell number. The arrangement of bacteria defines the position and organisation of bacteria that strongly depends upon the type of cell division. Sheathed Bacteria: These appear like a rod shape or filamentous structure and they mostly found in the aquatic habitat and sludge.Appendaged Bacteria: This group of bacteria possess an extension or outgrowth in the form of stalk, hypha or buds.Examples: Haloarcula vallismortis, Haloarcula marismortui etc. In 1980, box-shaped bacteria were isolated from the natural salt ponds. Box-shaped bacteria adhere to each other after cell division. Small cells are square-shaped, and large cells are rectangular. Box-shaped bacteria appear as a thin, flexible sheet with a smooth surface. Box-shaped Bacteria: They are square-shaped bacteria having flat or straight edges.Star-shaped Bacteria: Stella is a type of bacteria, which resembles a star.Examples: Candidatus savagella, Nocardia amarae, Alcaligenes paemba, Thiothrix sp. The filamentous bacteria are sometimes branched, resembling the filamentous structure of fungi, i.e. Filamentous Bacteria: Some bacteria are filamentous in structure by having a long and tubular shape.Examples: Mycoplasma pneumoniae, Deinococcus radiodurans, Mycoplasma genitalium etc. Pleomorphic Bacteria: This group of bacteria do not possess a characteristic shape and size and they exist in variable shapes throughout their life cycle.They usually appear singly.Įxamples: Treponema pallidum, Spirillum minus, Chlamydia trachomatis etc. Spirilla are small, curved and coiled in appearance. whereas spirillum is a singular form that represents a single helical-shaped bacterial cell. It is a plural form, which represents a large number of bacteria that possess a helical shape. They can appear either singly or in pairs, groups etc.Įxamples: Lactobacillus sp, Salmonella sp, Escherichia coli etc. Bacilli are small, cylindrical and elongated in appearance. Oppositely, coccus is a singular form representing a single rod-shaped bacterial cell. It is a plural form, which represents a bacterial population possessing a rod shape. ![]() They can appear singly or in pairs, chains, groups, clusters etc.Įxamples: Staphylococcus aureus, Streptococcus hominis, Neisseria gonorrhoea etc. Cocci are small, round and slightly flattened in shape. Conversely, coccus is a singular form, which represents a single spherical-shaped bacterial cell. It is a plural form, which represents a large number of bacteria possessing a spherical shape. Generally, there are three common shapes of bacteria, namely, cocci, bacilli and spirilla. The rigid cell wall decides the shape of bacteria. Bacteria can also function as a multicellular population rather than an individual organism. Even though of small size, bacteria can communicate with the other microorganisms through a mechanism called “ Quorum sensing”. Being a prokaryotic cell, the size of bacteria is smaller than the eukaryotic cells like fungi.īecause of bacteria’s small size, their structure becomes more complicated. The largest bacteria known so far is Thiomargarita namibiensis, which measures a size of 0.1-0.75 nm. In the most diverse group of bacteria, mycoplasma is a type of bacteria considered as the smallest organism (measures a size of 0.25 µm). Some bacteria possess a diameter of 80 µm and a length of 600 µm, which we can see through the naked eyes. The spherical shaped bacteria have an average diameter ranging from 0.5-2.0 µm, whereas the rod shaped bacteria have an average diameter of 0.25-1.0 µm. The bacterial size ranges from 0.5-1.0 µm, which you can observe in the highlighted portion of the image below. In this lesson, we will discuss the size range, common shapes and different arrangement of bacteria. Through microscopic observation, we can determine the morphological or physiological characteristics of bacteria based on bacterial shape and arrangement. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |