What is Eubacteria and its Characteristics? | Eubacteria

Eubacteria Definition

Eubacteria or “true” bacteria are unicellular, prokaryotic organisms. It has a lipid-containing cell membrane made from glycerol ester lipids. They are characterized by a lack of a nuclear membrane, a single circular chromosome, and cell walls made of peptidoglycan. They can be divided into two categories depending on the type of cell wall: gram-positive bacteria and gram-negative bacteria.

What are the characteristics of eubacteria?

Eubacteria, or microorganisms lacking a defined membrane nucleus, have several general characteristics. As prokaryotes, they do not have any membrane-bound organelles. Most eubacteria are enclosed by a cellular wall, which is made up of peptidoglycans in a cross-linked chain pattern.

This gives the bacteria cell wall the strength it needs to maintain its shape and size in changing environments. Small molecules can diffuse through the cell wall, but larger molecules and ions require carrier proteins and channel proteins to get into the cell. A popular classification system divides all living things into three areas: eubacteria, archaea, and eukaryotes.

What is the mode of nutrition in Eubacteria?

Domain Eubacteria are taken nutrition by both heterotrophic or Autotrophic. The best-known type of nutrition in eubacteria is heterotrophic, which means that they have to ingest food from other sources of organic carbon, mainly plant or animal matter. However, make their own food through photosynthesis called autotrophs.

Eubacteria respiration

Eubacterial respiration can be aerobic or anaerobic. Aerobic – Survive in the presence of oxygen (strict aerobes) or switch to anaerobic respiration in the absence of oxygen (facultative anaerobes). The anaerobes go through a form of respiration called fermentation. Some of the anaerobes can live in the presence or absence of oxygen. These are called facultative anaerobes.

How does Eubacteria reproduce?

Eubacteria reproduce in two main ways, Sexually and Asexually. Sexual reproduction involves the exchange of genetic material through conjugation, transduction, and transformation. While Asexual reproduction in eubacteria involves binary fission, endospore formation, fragmentation, budding, and conidia formation.

Eubacteria structure
Structure of Eubacteria

What are Structural characteristic of Eubacteria?

Some eubacteria may have flagella or a protrusion of protein filaments that are used for movement. Other Eubacteria may have pili, small protrusions on the outside of the cell that is used to adhere to surfaces and transfer DNA. If a large number of eubacteria adhere to a surface and are surrounded by a polysaccharide sac, it is called a biofilm. This complex has a high level of antibiotic resistance.

Plasmids are also found in bacteria that are separated from the circular DNA of the bacteria. Plasmids are also known as “replicons” and are autonomous replicating DNA molecules. However, not all plasmids replicate in bacteria. These elements enable a horizontal gene transfer, whereby a bacterium can acquire new genes and thus characteristics.

They primarily support the rapid mutation of bacteria into various factors. Similar to the other genetic material, the plasmids can be transferred to daughter cells during replication. They are the DNA structure commonly used in research because they are relatively easy to manipulate, implant, and measure.

Types of Eubacteria

Types of Eubacteria can be distinguished according to a number of characteristics:

  • Shape – Round (coccus), rod-like (bacillus), comma-shaped (vibrio), or spiral (spirilla/spirochete).
  • Cell wall composition – Gram-positive or Gram-negative.
  • Gaseous requirements – Anaerobic or aerobic.
  • Nutritional patterns – Autotrophic or heterotrophic.

Eubacteria are typically divided into five different phyla based on the number of characteristics:

  1. Chlamydia is often parasitic bacteria.
  2. Cyanobacteria are most commonly known to be aquatic and gain energy through photosynthesis.
  3. Proteobacteria: all “Proteobacteria” are Gram-negative (though some may stain Gram-positive or Gram-variable in practice), with an outer membrane mainly composed of lipopolysaccharides. Many moves about using flagella, but some are nonmotile or rely on bacterial gliding.
  4. Firmicutes: It is a phylum of bacteria, most of which have gram-positive cell wall structure. A few, however, such as Megasphaera, Pectinatus, Selenomonas, and Zymophilus, have a porous pseudo-outer membrane that causes them to stain gram-negative.
  5. Spirochetes: It is long, thin, spiral-shaped bacteria that are known to cause Lyme disease. They differ from the other types of bacteria in their helical shape and movement. They usually move by rotating along their axis.

Bacteria commonly take on one of three shapes: bacilli, cocci, and spirilla. Bacilli have a rod shape, cocci have a spherical shape, and spirilla have a spiral or wave shape. Their shape was often used as a classification system until recently. Bacteria may stay linked after division, forming other shapes such as clusters, filaments, and tight coils.

Examples of Eubacteria

Eubacteria are common bacteria. You’ve probably heard several of them, like Streptococcus pneumoniae, which causes pneumonia, or Lactobacillus, which is a good bacteria in our gut.

When it comes to eubacteria, there are typically 5 different groups that these bacteria fall into proteobacteria, cyanobacteria, chlamydia and spirochetes, and gram-positive. Immerse yourself in eubacteria examples from each group.

Escherichia Coli

Escherichia coli, better known by the street name E. coli. These bacteria are usually innocent in your digestive tract, but the wrong strain can destroy your digestive system.

E. coli is one of the largest groups of bacteria known as proteobacteria and comprises several strains. For example, E. coli O157: H7 is a strain that causes intestinal infections. Other E. coli strains cause urinary tract infections. In fact, MedMD finds that 75-95% of UTI infections are caused by E. coli.


Cyanobacteria, known as blue-green algae, are photosynthetic bacteria that occur in large colonies in water. So not only do they making their own food, but you can also see these bacteria without a microscope if the colony is large enough.

Interestingly enough, cyanobacteria have two pretty amazing bragging rights. In addition to being the oldest fossils, Berkley University also states that cyanobacteria contributed to the evolution of plants.

Borrelia Burgdorferi

Borrelia burgdorferi, also known as B. burgdorferi, falls into a group of bacteria called spirochetes. They get this name because of their unique spiral shape under the microscope. While a spiral bacterium sounds like a good time, Borrelia burgdorferi is anything but.

B. burgdorferi causes Lyme disease in humans. As a rule, B. burgdorferi does not cause any problems with ticks in most small animals. However, when it is passed on to humans, it causes an infection with a variety of symptoms, including fever and rash.

Chlamydia Trachomatis

Chlamydia bacteria belong to the Chlamydiaceae family and are gram-negative, immobile bacteria. A special type of chlamydial bacteria is Chlamydia trachomatis.

Chlamydia trachomatis is one of the “bad bacteria” and causes trachoma, a disease that causes 1.9 million people to go blind. This disease spreads through person-to-person contact and flies. Another strain of these bacteria is also known to cause the sexually transmitted disease chlamydia.

Staphylococcus Aureus

Last but not least is good old Staphylococcus aureus or Staphylococcus. Staphylococcus aureus is a gram-positive bacterium, which means that it retains its purple color in a gram stain test. Staphylococcus is a member of the Staphylococcaceae family and is a common germ that most people carry around in their noses and on their skin.

However, this example of eubacteria can cause serious infections under the right conditions. It is the culprit for the infection that is commonly known as MRSA. In healthcare, MRSA is a serious infection because it is resistant to common antibiotics.

Top Questions

What is eubacteria?

Eubacteria, or “true” bacteria, are single-celled prokaryotic microorganisms that have a range of characteristics and are found in various conditions throughout all parts of the world. Since eubacteria are so common, this group comprises one of the three domains of life: Bacteria

Why eubacteria are called “true” bacteria?

Eubacteria are also known as true bacteria because “Eu” means true. True bacteria is just another word for eubacteria.

What characteristics do eubacteria have?

Eubacteria or “true” bacteria are unicellularprokaryotic organisms. It has a lipid-containing cell membrane made from glycerol ester lipids. They are characterized by a lack of a nuclear membrane, a single circular chromosome, and cell walls made of peptidoglycan. They can be divided into two categories depending on the type of cell wall: gram-positive bacteria and gram-negative bacteria.

Is eubacteria heterotrophic Photoautotrophic or Chemoautotrophic?

Eubacteria mainly obtain nutrition through absorption, meaning they are heterotrophs. However, some obtain nutrition through photosynthesis or chemosynthesis, meaning those are autotrophs. Therefore, eubacteria are heterotrophicphotoautotrophic, and chemoautotrophic.

What are the types of eubacteria?

Eubacteria commonly take on one of three shapes: bacilli, cocci, and spirilla. Bacilli have a rod shape, cocci have a spherical shape, and spirilla have a spiral or wave shape. Their shape was often used as a classification system until recently. Bacteria may stay linked after division, forming other shapes such as clusters, filaments, and tight coils.

What are some common examples of eubacteria?

Escherichia Coli. better known by its street name E.coli
Borrelia Burgdorferi.
Chlamydia Trachomatis.
Staphylococcus Aureus.