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Sep 22, 2024 · There are three basic shapes of bacteria: coccus, bacillus, and spiral. Based on planes of division, the coccus shape can appear in several distinct arrangements: diplococcus, streptococcus, tetrad, sarcina, and staphylococcus.
- Bacterial Size
- Bacterial Shape
- Arrangements of Cocci
- Arrangement of Bacilli
- Arrangement of Spiral
- Other Shapes and Arrangements
- References
- Sources
The unit of measurement used in bacteriology is the micron (micrometer) which is one-thousandth of a millimeter.Bacteria are, in general one-tenth the size of the eukaryotic cell. On average, the size of bacteria ranges from 0.5 to 5 µm.However, they can be as tiny as 0.3 µm and as large as 0.7mm.The limit of resolution with the unaided eye is about 200 microns, and as many bacteria are smaller than this size, they are not visible with naked eyes.Image created using biorender.com 1. Most of the bacteria have a rigid cell wall that provides a definite shape to the bacteria while protecting the internal components. 2. Even though this characteristic is valid for the majority of bacteria, they vary in shape that allows them to be classified into different groups based on their forms. 3. This w...
Cocci bacteria can be arranged either singly, in pairs, in groups of four, in chains, in clusters or cubes consisting of eight cells.These cells remain attached during cell division.Bacillus
1. Bacilli are the bacteria which are rod-shaped and are present as single cells. 2. These bacteria can form endospores and are facultative anaerobes. 3. Examples: Salmonella enterica subsp, Bacillus cereus, and Salmonella choleraesuis.
Diplobacilli
1. As in Diplococci, Diplobacilli also exists in pairs. 2. After cell division, the two cells do not divide and grow in an attached arrangement. 3. Examples: Coxiella burnetii, Klebsiella rhinoscleromatis, Moraxella bovis.
Streptobacilli
1. In this group, bacteria are arranged in chains. 2. This results from cell division in a single chain. 3. Examples: Streptobacillus moniliformis, Streptobacillus Levaditi, Streptobacillus felis, Streptobacillus hongkongensis.
Vibrio
1. These are the slightly curved bacteria resembling a comma shape. 2. Examples: Vibrio mytili, Vibrio anguillarum, Vibrio parahaemolyticus, Vibrio cholera.
Spirochetes
1. Spirochetes are spiral bacteria having a helical shape. 2. These are flexible and have an axial filament which helps in motility. These filaments are essential distinguishing character between spirochetes and other bacteria. 3. These filaments run throughout the length of the bacteria and thus, help in twisting the motion of the bacteria. 4. Examples: Leptospiraspecies (Leptospira interrogans), Treponema pallidum, Borrelia recurrentis.
Spirilla
1. These bacteria are similar in structure with spirochetes but are more rigid. 2. They, too, have a flagellum but lack the endoflagella like in spirochetes. 3. Examples: Campylobacter jejuni, Helicobacter pylori, Spirillum winogradskyi.
Appendaged Bacteria 1. The bacteria that produce a unique structure like pillus or fimbriae are called appendaged bacteria. 2. These bacteria are more virulent than other bacteria that do not form these appendages. 3. Example: Neisseria gonorrheae, the agent of Gonorrhea. Box-shaped/ Rectangular Bacteria 1. Box-shaped bacteria are rectangular in sh...
Young K. D. (2007). Bacterial morphology: why have different shapes?. Current opinion in microbiology, 10(6), 596–600. https://doi.org/10.1016/j.mib.2007.09.009Al-mohanna, Moshtaq & H., quine. (2016). MORPHOLOGY AND CLASSIFICATION OF BACTERIA.Constantino MA et al.(2016). Helical and rod-shaped bacteria swim in helical trajectories with little additional propulsion from helical shape. Science Advances. DOI: 10.1126/sciadv.16016613% – https://www.microscopemaster.com/bacteria-size-shape-arrangement.html3% – http://europepmc.org/articles/PMC21695032% – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2169503/2% – https://microbiologyinfo.com/different-size-shape-and-arrangement-of-bacterial-cells/Mar 28, 2024 · Bacterial cell dimensions, though minute in nature, present a wide array of sizes indicative of the diversity inherent within bacterial phylogeny. The metric predominantly employed for such measurements in bacteriology is the micron (µm), which is a unit representing one-thousandth of a millimeter.
Aug 10, 2022 · Due to the presence of a rigid cell wall, bacteria maintain a definite shape, though they vary as shape, size and structure. When viewed under light microscope, most bacteria appear in variations of three major shapes: the rod (bacillus), the sphere (coccus) and the spiral type (vibrio).
According to many microbiology books, the average size of most bacteria is between 0.2 and 2.0 micrometer (diameter). However, there are some that hold this to range between 1 and 10 micrometers. This, however, only considers the diameter of the organisms and not the length.
Jan 26, 2023 · Most bacteria have a rigid cell wall that provides a definite shape to the bacteria while protecting the internal components. The wide diversity of shapes is defined by the bacterial cell wall and cytoskeleton.
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Simply put, bacteria with different shapes present different physical features to the outside world, and these features help cells cope with and adapt to external conditions.
