Bacteria are single-celled and are classified under the domain Prokaryota. As such, they lack membrane-bound organelles like those found in eukaryotes.
Although they are all microscopic organisms that can be found in various environments in nature, bacteria widely vary in size, shape, and arrangement.
* The majority of bacteria species are microscopic, however, studies have identified large bacteria that can be seen with the naked eye.
Bacteria display a large diversity of cell morphologies and arrangements by Mariana Ruiz LadyofHats [Public domain], wikipedia commons
In general, bacteria are between 0.2 and 2.0 um - the average size of most bacteria. Research studies have shown their size to play an important role in survival over time.
Due to their small size, bacteria are able to exploit and thrive in various microenvironments. These include such environments as the vertical gradients in intertidal marine sediments in which various types of bacteria have been found. Because various microorganisms are absent in such environments, bacteria successfully exploit resources available and thrive in such environments.
The small size of bacteria is also beneficial for parasitism and oligotrophy. Bacteria can continue relying on a range of hosts (large and small) for their nutrition. In addition, they can also live and survive in environments that contain a low concentration of nutrients; for instance, a group of bacteria known as oligotrophic bacteria.
Bacteria have a high surface area to volume ratio that allows them to take up as many nutrients as possible for survival. In the process, they are able to continue growing and reproducing at a steady rate.
In bacteriology, the micron (micrometer) is the primary unit of measurement: I micrometer (um) is one-thousandth of a millimeter.
* Given that the limit of resolution for a human eye (naked eye) is between 100 and 200 um (about the diameter of a human hair) then the majority of bacteria cannot be seen with the naked eye.
Relative scales of eukaryotes, prokaryotes, viruses, proteins and atoms. Created by TimVickers, vectorized by Fvasconcellos [Public domain]
The following are different sizes of bacteria:
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.
For instance, whereas E. coli bacteria range between 1.1 and 1.5 um in diameters, B.anthracisrange between 1.0 and 1.2um while B.subtilisrange between 0.25 and 1.0um in diameter. They also vary in length when compared to each other.
There has been some debate about their classification but some of the smallest bacteria are microorganisms known as nanobacterium.
They are characterized by their slow growth underaerobicconditions as well as being Gram-negative in nature. Although they have been shown to range between 0.2 and 0.5um (200 to 500 nanometers) there have been studies where some were found to filter through 0.1um filters.
Some examples of these bacteria include Mycoplasmas (about 0.25um), Haemophilusinfluenzaewhich ranges between 0.2 and 0.3um and Mycoplasmagallicepticumwhich range between 200 and 300 nanometers in diameter.
* Although such bacteria as Mycoplasma lack a cell wall, they can exist independently. They are found in such hosts as human beings, plants and a variety of insects.
Some bacteria are large enough to see with the naked eye. For instance, whereas Schaudinnum bütschlii that measure between 4 and 5um in diameter are considered to be large bacteria, Thiomargaritanamibiensismay grow to be as large as 0.75mm in diameter. This makes them some of the largest bacteria ever discovered. As such, they can be seen with the naked eye - when they reach such sizes.
*The Thiomargaritanamibiensisis a Gram-negative bacterium that is coccoid in shape. It was discovered in ocean sediments in Namibia (Southwest of Africa).
Shape and Arrangement
Morphologically, bacteria are microscopic single-celled organisms that are small in size andlackmembrane boundorganelles. A majority of these organisms also have a cell wall and capsule that protects the inner contents of the cell where the nucleoid, ribosome, plasmid, and cytoplasm are found.
While a majority of bacteria share these characteristics, they vary in shape which allows different types of bacteria to be classified based on their general shape.
The following are the major categories of bacteria based on their shapes:
Cocci bacteria appear spherical or oval in shape. For the most part, the shape is determined by the cell wall of the organism and therefore varies from one type of cocci bacteria to another. Cocci bacteria may exist as single cells or remain attached to each other.
Attached Cocci bacteria include:
Diplococci bacteria- Diplococci bacteria are the type of cocci bacteria that occur as a pair (two joined cells).
Some examples of Diplococci bacteria include:
- Enterococcus spp
- Neisseria gonorrhea
While some of these cells may be truly round shaped, others may appear elongated (ovoid) or bean-shaped/kidney shaped. For instance, some Neisseria cells may appear round while others are bean-shaped when viewed under the microscope.
Tetrad bacteria- Tetrad bacteria are arranged in groups of four cells. Following division, the cells remain attached and grow in this attachment.
Common examples of Tetrad bacteria include:
Sarcinaesarcina/Bacteria- Sarcina bacteria occur in groups of 8 cells. Unlike tetrads that divide into two planes, Sarcinae is produced through the perpendicular plane division.
Some of the characteristics associated with these bacteria include being strict anaerobes, Gram-positive bacteria and that measure between 1.5 and 3.0 um.
Examples of Sarcinae bacteria include:
- Sarcina ventriculi
Streptococci Bacteria- Streptococci bacteria are a type of bacteria that arrange in a chain form (resembling chains). A majority of these bacterial cells are also ovoid in shape and may form paired chains.
As members of the family Streptococcaceae, this group of bacteria is characterized by being non-motile, Gram-positive organisms.
Examples of Streptococcus bacteria include:
Staphylococci Bacteria- Staphylococci Bacteria are a type of bacteria that form grape-like clusters. This type of arrangement is the result ofdivisionthat occurs in two planes. Two of the main characteristics of these organisms are that they are immobile, Gram-positive bacteria.
Examples of Staphylococci bacteria include:
- Staphylococcus aureus
Bacillus Bacteria (Rod-Shaped)
Bacillus bacteria have the following traits:
- Are all rod-shaped
- Form endospores
- Facultative anaerobes
Like cocci bacteria,bacillusbacteria are also arranged differently. While some exist as single, unattached cells (e.g. Salmonellaentericasubsp, Bacillus cereus, and Salmonellacholeraesuis), others are attached.
The following are the different types of bacillus arrangements:
Diplobacilli bacteria -Like Diplococci bacteria, Diplobacillioccur in pairs. Following cell division, the two cells do not separate and continue existing as a pair.
Examples of Diplobacillibacteria include:
Streptobacilli- Streptobacilli bacteria occur as elongated chains. As such, they are the result ofdivisionon a single plane.
Common examples of Streptobacilli include:
- Streptobacillus Levaditi
Coccibacilli bacteria- Compared to other bacilli, Coccibacillibacteria are shorter in length and thus appear stumpy.
Examples of Coccibacilliinclude:
- Chlamydia trachomatis
* Palisades are another type of bacilli bacteria. Cell division of these bacteria results in a type of arrangement that resembles a picket fence. One of the best examples ofpalisadesis the Corynebacterium diphtheria that is responsible for diphtheria.
Unlike cocci and bacilli bacteria, some types of bacteria appear curved when viewed under the microscope. However, they vary in shape making it possible to differentiate them from each other.
Vibrio bacteria-Generally,vibriobacteria are comma-shaped and thus not fully twisted (curved rods).
Examples of Vibrio bacteria include:
- Vibrio mytili
Spirochete- Spirochetes are characterized by a helical shape. Spirochetes are also flexible and have been shown to produce mycelium. The movement involves the use of axial filaments, which is one of the distinguishing features between the bacteria and other types of bacteria.
* Axial filaments in spirochetes are located between the inner and outer membrane. They run along the length of the bacteria and are responsible for the twisting motion of the organisms.
Examples of Spirochetes include:
Spirilla bacteria-Like Spirochetes, Spirilla bacteria possess a helical shape. However, they are more rigid and have the typical flagella found in other types of bacteria.
Some examples of Spirilla bacteria include:
Other Types of Bacteria based on the Shape
Some bacteria possess various odd shapes that distinguish them from other types of bacteria.
- Rectangular bacteria- They appear rectangular in shape e.g. Haloarculamarismortui
- Star-shaped bacteria- Look like stars (star-shaped) e.g. Stellahumosa
- Haloarcula- Triangular in shape
- Pleomorphic bacteria- Bacteria with the ability to change their shape and size in different environments, e.g. M. pneumonia
- Stalked bacteria- These include such bacteria as C.crescentusthat possess a stalk on one end of the cell
More on Cells:
Eukaryotes - Cell Structure and Differences
Prokaryotes - Cell Structure and Differences
Protists - Discovering the Kingdon Protista in Microscopy
- Paramecium - Classification, Structure, Function and Characteristics
- Vorticella - Characteristics, Structure, reproduction and Habitat
Diatoms- Classification and Characteristics
Fungi - Mold Under the Microscope, Aspergillus type
Algae - Reproduction, Identification and Classification
Protozoa - Anatomy, Classification, Life Cycle and Microscopy
Bacteria- Morphology, Types, Habitat, looking at anaerobes, Eubacteria
Archaea - Definition, Examples, Characteristics and Classification
- What are Viruses?
- How do Bacteria cause Disease?
- Virus Vs Bacteria
- How do antibiotics kill bacteria?
- List of Diseases caused by Bacteria
- Does Peroxide kill Bacteria
- How Long Do Bacteria Live?
Return to Gram positive and Gram negative bacteria page
Return to Bacteriology main page
Learn more here about Anaerobes
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Kevin D. Young. (2006). The Selective Value of Bacterial Shape. American Society for Microbiology.
Moshtaq Talip Al-mohanna. (2016). Morphology And Classification Of Bacteria. ResearchGate.
Siamak Yaghobee and Mojtaba Bayani. (2015). What are the nanobacteria?. ResearchGate.
James T. Staley. (1999). Size Limits of Very Small Microorganisms: Proceedings of a Workshop.
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Morphology Of Bacteria Overview Bacteria are prokaryotic, unicellular forms of biological cells.....
Although most bacteria have this property, there are those that differ in shape, allowing them to be divided into several groups according to their shapes.. Bacteria can be divided into the following common shape categories:. Cocci bacteria can be grouped in a variety of ways, including individually, in pairs, in groups of four, in chains, in clusters, or in eight-cell cubes.. During cell division, these cells stay together.. This configuration happens when two bacterial cells form a pair (joined together).. Examples include Neisseria gonorrhoea, Moraxella catarrhalis, Streptococcus pneumonia, and Enterococcus species.. Tetrad bacteria are grouped in a cluster of four cells that stay connected after cell division and continue to develop there.. The bacterial cells are arranged into a group of eight cells in this configuration.. Bacilli are rod-shaped solitary cells of bacteria that are present.. The two cells do not split again after cell division and continue to grow together.. Pallisades are a particular form of bacilli bacteria that have a bent point of division during cell division, giving them the appearance of a picket fence.. Examples include M. genitalium and Mycoplasma pneumoniae.. Bacterial morphology: why have different shapes?.
Morphology of Bacteria: Know what are the different types of bacterial morphology. Also, check why do bacteria have different morphology.
A bacteria’s greatest distinguishing characteristic is its morphology or shape.. Arrangements of Cocci a. Cocci bacteria can be organised individually, in pairs, in four-cell groups, in chains, in clusters, or in eight-cell cubes.b.. During cell division, these cells stay together.. Cocci have a gram-positive cell wall with a thick peptidoglycan layer or a gram-negative cell wall with a thin peptidoglycan layer.d.. In this type, the bacteria are organised in long chains here.ii.. The bacterial cells form an eight-cell cluster in this configuration.ii.. C. Spiral This group of microorganisms includes bacteria that are either helical-shaped or curved or comma-shaped .. Some of the other shapes and arrangements are as follows: 1.Filamentous Bacteria i.. The bacteria that belong to this group does not have or possess a specific shape.. Examples: Mycoplasma .. What are the three different types of bacterial morphology?Ans: The three different types of bacterial morphology are cocci, bacillus and spiral.. What do you mean by morphology?Ans: Morphology is the study of the shape and structure of organisms.
Different Size, Shape and Arrangement of Bacterial Cells Cocci. Bacilli (Rod-shaped). Spiral. Arrangements of Cocci. Arrangement of Bacilli.
2 Size of Bacterial Cell 2.1 Benefits of Bacterial Cell Being Small In Size.... Different Size, Shape and Arrangement of Bacterial Cells. You have to know about the Shapes, Size, and arrangements of bacterial cells before going to dip in microbiology.. The size, shapes, and arrangement of bacterial cells varies based on the types of species.. Bacterial cells are much smaller than eukaryotic cells, generally one-tenth of the size of the eukaryotic cell.. Different Size, Shape and Arrangement of Bacterial CellsThe primary unit we used to measure the size of a bacterial cell is micron (micrometer).. Average Size Bacteria The average size of a bacterial cell varies between 0.2 to 2.0 micrometers (diameter).. Smallest Size Bacteria The size range of the smallest bacteria is between 0.2 and 0.5um (200 to 500 nanometers) there have been studies where some were found to filter through 0.1um filters.. This variation in shape of a bacterial cell is determined by the bacterial rigid cell wall and cytoskeleton.. Bacillus: These types of bacterial cells appear as rod shapes.. Image: Different Size, Shape and Arrangement of Bacterial Cells | Created By: Microbiologynote.com The shape of a bacterial cell depends on a special protein called MreB.. When bacterial cells appear spherical or oval in shape, this type of bacteria are called coccus.. Image: Monococci and Diplococci | Created By: Microbiologynote.com When a coccus cell stays singly in a plane, then this type of coccus cells are called monococci.. When a bacterial cell completes one or more complete turns and produces helical shape and stays rigid, then these bacteria are called spirilla.
Morphology Of Bacteria Overview Bacteria are prokaryotic, unicellular forms of biological cells.....
Bacteria can be divided into the following common shape categories:. Cocci bacteria can be grouped in a variety of ways, including individually, in pairs, in groups of four, in chains, in clusters, or in eight-cell cubes.. During cell division, these cells stay together.. This configuration happens when two bacterial cells form a pair (joined together).. Examples include Neisseria gonorrhoea, Moraxella catarrhalis, Streptococcus pneumonia, and Enterococcus species.. Tetrad bacteria are grouped in a cluster of four cells that stay connected after cell division and continue to develop there.. The bacterial cells are arranged into a group of eight cells in this configuration.. Bacilli are rod-shaped solitary cells of bacteria that are present.. The two cells do not split again after cell division and continue to grow together.. Pallisades are a particular form of bacilli bacteria that have a bent point of division during cell division, giving them the appearance of a picket fence.. Examples include M. genitalium and Mycoplasma pneumoniae.. Bacterial morphology: why have different shapes?.
What is bacteria? Bacterial Size. Bacterial Shape. Cocci. Bacilli (Rod-shaped). Spiral. Arrangements of Cocci. Arrangement of Bacilli.
Most of the bacteria have a rigid cell wall that provides a definite shape to the bacteria while protecting the internal components.. Even though bacteria have a wide variety of shapes, anyone genus typically exhibits a limited subset of morphologies, indicating that, with a universe of shapes to choose from, individual bacteria adopt only those that are adaptive.. The bacteria that are oval or spherical in shape are included called cocci bacteria.. Bacilli bacteria are among the first bacteria to have arisen, and this shape is said to be not as advantageous as other shapes.. Tetrad bacteria are arranged in a group of four cells that remain attached and grow in the attachment after cell division.
Morphology of Bacteria: Know what are the different types of bacterial morphology. Also, check why do bacteria have different morphology.
The bacteria, which is a single cell, splits into two identical daughter cells throughout this procedure.VII.. The bacteria that are oval or spherical in shape are known as cocci bacteria .b.. These bacteria belong to the Streptococcaceae family, which is characterised by Gram-positive bacteria and a lack of motility.iii.. Tetrads i. Tetrad bacteria are organised in a group of four cells that remain connected during cell division and development in the attachment.ii.. Bacilli bacteria were among the earliest to emerge, and their form is considered to be less favourable than that of other bacteria.. Appendaged Bacteria i. Appendaged bacteria are bacteria that generate a distinct structure, such as pillus or fimbriae.ii.. These bacteria are more virulent when compared to the other bacteria that do not form these appendages.iii.. Box-shaped/ Rectangular Bacteria i. Bacteria with a box-like form or that are rectangular in shape.ii.. What are the two main classifications of bacteria?Ans: The two main classifications of bacteria are gram positive-bacteria and gram-negative bacteria.. What is the most common type of bacteria?Ans: The most common type of bacteria is Escherichia coli .
DefinitionBacteria are single-celled and are classified under the domain Prokaryota. As such, they lack membrane-bound organelles like those found in eukaryotes. Although they are all microscopic organisms that can be found in various environments in nature, bacteria widely vary in size, shape, and...
In general, bacteria are between 0.2 and 2.0 um - the average size of most bacteria.. While a majority of bacteria share these characteristics, they vary in shape which allows different types of bacteria to be classified based on their general shape.. Diplococci bacteria - Diplococci bacteria are the type of cocci bacteria that occur as a pair (two joined cells).. Tetrad bacteria - Tetrad bacteria are arranged in groups of four cells.. Some of the characteristics associated with these bacteria include being strict anaerobes, Gram-positive bacteria and that measure between 1.5 and 3.0 um.. Streptococci Bacteria - Streptococci bacteria are a type of bacteria that arrange in a chain form (resembling chains).. Staphylococci Bacteria - Staphylococci Bacteria are a type of bacteria that form grape-like clusters.. Unlike cocci and bacilli bacteria, some types of bacteria appear curved when viewed under the microscope.. Spirilla bacteria -Like Spirochetes, Spirilla bacteria possess a helical shape.. Some bacteria possess various odd shapes that distinguish them from other types of bacteria.. Rectangular bacteria - They appear rectangular in shape e.g. Haloarculamarismortui Star-shaped bacteria - Look like stars (star-shaped) e.g. Stellahumosa Haloarcula - Triangular in shape Pleomorphic bacteria - Bacteria with the ability to change their shape and size in different environments, e.g. M. pneumonia Stalked bacteria - These include such bacteria as C.crescentusthat possess a stalk on one end of the cell. Virus Vs Bacteria How do antibiotics kill bacteria?. List of Diseases caused by Bacteria Does Peroxide kill Bacteria How Long Do Bacteria Live?
ADVERTISEMENTS: In this article we will discuss about:-1. Size of Bacterial Cell 2. Shape of Bacterial Cell 3. Arrangement. Size of Bacterial Cells: Individual bacterial cells are not visible to the unaided eye. In general, bacterial cells do not exceed 1 μm (micrometer or micron) in diameter, though their length may vary widely. Some bacteria […]
Size of Bacterial Cells: Individual bacterial cells are not visible to the unaided eye.. Due to their small size, bacteria have a much greater surface/volume ratio than most eukaryotic organisms having larger cells.. For example, the rate of oxygen uptake (μl/mg dry weight/hr) of most aerobic bacteria is approximately 10 times faster than that of another unicellular but larger organism—yeast—and 100 times faster than the cells of animal tissues.. Shape of Bacterial Cells: Bacterial cells are bound externally by a rigid wall which gives bacteria their characteristic shape.. That the cell wall is responsible for giving shape to bacterial cells is also shown when the wall is removed by enzymes.. Some bacteria have also flexible cells.. For example, a group of bacteria produces a narrow extension from the cell which is used either for attachment or for producing daughter cells by budding.. Mycoplasmas, which lack a rigid cell wall, exhibit many types of cells without a definite shape and size.. Arrangement of Bacterial Cells: Bacteria multiply by binary fission which means a bacterial cell divides to form two identical daughter cells.. In many bacteria, the daughter cells separate from each other soon after the division.. But in many others, the newly formed cells do not separate and adhere to each other to give characteristic cell arrangements.. The different types of cell arrangement result from the cell division at different planes.. These cell arrangements of spherical bacteria are shown in Fig.. Generally, the cylindrical bacteria — bacilli, do not exhibit characteristic cell arrangements as the cocci do.. The cell arrangements of rod-shaped bacteria are shown in Fig.
Bacterial shape and arrangement vary among different species and exists in many forms. In this content, bacterial shape and arrangement are explained.
Bacteria exist in many forms, but the most common types are bacilli, cocci and spirilla.. Size of Bacteria Shape of Bacteria Video Bacterial Arrangement Conclusion. 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 ).. Because of bacteria’s small size, their structure becomes more complicated.. The bacteria are grouped into four types based on bacterial cell arrangement and cell number .. Arrangement of Spirilla The spirillum cells have a rigid spiral structure and they usually exist singly.
Bacteria are single-celled microorganisms with prokaryotic cells, which are single cells that do not have organelles or a true nucleus and are less complex than eukaryotic cells.
Bacteria are single-celled microorganisms with prokaryotic cells, which are single cells that do not have organelles or a true nucleus and are less complex than eukaryotic cells.. Bacteria with a capital B refers to the domain Bacteria, one of the three domains of life.. Bacteria are extremely numerous, and the total biomass of bacteria on Earth is more than all plants and animals combined.. Bacteria first arose on Earth approximately 4 billion years ago, and they were the first forms of life on Earth.. Eukaryotic cells, which make up all protists, fungi , animals, and plants, also contain what was once bacteria; it is thought that the mitochondria in eukaryotes, which produce energy through cellular respiration , and chloroplasts in plants and algae , which produce energy through photosynthesis , both evolved from bacteria that got taken up into cells in an endosymbiotic (mutually benefiting) relationship that became permanent over time.. Bacteria also have a cell membrane and a cell wall that is often made of peptidoglycan .. Many bacteria need a cell wall in order to survive.. Bacteria reproduce asexually, so the two daughter cells that result from binary fission have the same DNA as the parent cell.. Gram staining is used for general identification of bacteria or to detect the presence of certain bacteria; it cannot be used to identify bacteria in any specific way, such as at a species level.. Examples of gram-positive bacteria include the genera Listeria, Streptococcus, and Bacillus , while gram-negative bacteria include Proteobacteria, green sulfur bacteria, and cyanobacteria.. Lactobacillus acidophilus is another bacillus-shaped species of bacteria naturally found in places like the intestines and vagina, where it protects against harmful bacteria.. Some bacteria can be extremely harmful, such as Clostridium botulinum , the bacteria that causes botulism.. Prokaryote – An organism that has a simple prokaryotic cell ; bacteria and archaea are prokaryotes.. Star-shaped bacteria, such as those in the genus Stella , are not as common as cocci, bacilli, and spiral bacteria.