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Types of Microorganisms and Their Characteristics

  • Zoology

In this types of microorganisms and their characteristics post we have briefly explained about 5 types of microorganisms bacteria, archaea, fungi, protozoa, algae, viruses, multicellular animal parasites

Microorganisms constitute a significant portion of the Earth’s living matter and play a significant role in maintaining the Earth’s ecosystem. Microorganisms, also known as microbes, are microscopic living organisms found as multicellular, unicellular as cell clusters. 

Microorganisms are common throughout nature and beneficial to our lives; however, certain types can be harmful to humans. 5 types of microorganisms are archaea, bacteria, fungi, protozoa algae, and viruses.

Types of Microorganisms and Their Characteristics

Types of Microorganisms and Their Characteristics. Image Source: 

5 Types of Microorganisms


Bacteria are unicellular organisms one of the 5 types of microorganisms, and they are classified as prokaryotic due to the absence of a nucleus. They come in four primary forms such as Bacillus (rod shape) and Coccus (spherical shape), and Spirilla (spiral shape), along with vibrio (curved shape). The majority of bacteria have a peptidoglycan cell wall. They divide through binary fission, and they may have flagella for movement. The differences in their cell walls’ structure are an important factor in classifying the organisms.

Based on how the cell’s wall-stains the cell wall, bacteria are classified as Gram-positive or Gram-negative using this staining technique. Bacteria are further classified by their reaction to oxygen in gaseous form into the following categories that include aerobic (living in oxygen) and anaerobic (living without oxygen) as well as facultative anaerobes (can be found in both environments).

Based on the method they get energy the way they obtain energy, bacteria are classified as autotrophs or heterotrophs. Autotrophs create their food using sunlight’s energy or chemical reactions; they are referred to as Chemoautotrophs. Heterotrophs gain energy through taking in other organisms. Bacteria that use decaying forms as a source of energy are saprophytes.


Archaea also known as Archaebacteria one of the 5 types of microorganisms differ from real bacteria in the structure of their cell walls and do not contain the peptidoglycans. They are prokaryotic cells that have an inclination to endure the extreme conditions of their environment. According to their habitats they are all Archaeans can be classified into three categories methanogens (methane-producing organisms) and the halophiles (Archaeans living in salinity-rich environments) and thermophiles (Archaeans live in extremely high temperatures) and psychophiles (cold-temperature Archaeans). 

Archaeans utilize different sources of energy including carbon dioxide, hydrogen gas and sulfur. They also utilize sunlight to generate the energy they require, though not in the like plants do. They absorb sunlight through their membrane pigment called the bacteriorhodopsin. The light molecule reacts with it, creating the energy molecule, adenosine triphosphate (ATP).


Fungi (mushroom as well as molds and yeasts) one of the 5 types of microorganisms are cells that are eukaryotic (with an actual nucleus). The majority of fungi are multicellular, and their cell walls are comprised of Chitin. They get nutrients through absorption of organic matter from their surroundings (decomposers) or through the symbiotic relationship to plants (symbionts) or through hostile relationships with hosts (parasites). They are characterized by their filamentous tubes known as hyphae which assist in the absorption of materials. The hyphae collection is known as mycelium. The fungi reproduce by releasing spores.


Protozoa one of the 5 types of microorganisms is a unicellular aerobic eukaryote. They possess a nucleus, complicated organelles, as well as get nutrition through absorption or by means of special structures. They are the biggest collection of organisms on the planet in terms of number as well as biomass and diversity. The cell walls of their cells are comprised of cellulose. 

Protozoa have traditionally been classified by their method of movement: flagellates make the food they consume and employ their whip-like structures to propel forward and ciliates have tiny hairs which beat to create movements, and amoeboid have pseudopodia or false feet that are used for locomotion and feeding and sporozoans do not have any motors. They also have various methods of nutrition. This classifies them as heterotrophs or autotrophs.


Algae, also known as blue-green algae or cyanobacteria one of the 5 types of microorganisms are eukaryotes that are multicellular or unicellular which get their food through photosynthesis. They reside in damp soil, water and rock and produce carbohydrates and oxygen that are utilized in other living organisms. The theory is that cyanobacteria represent the ancestors of the green land plants.


The viruses are non-cellular organisms one of the 5 types of microorganisms composed of a nucleic acid base (DNA or RNA) and the protein coat. While viruses can be classified as microorganisms they aren’t considered to be living organisms. The virus cannot reproduce outside of an infected cell, and they are not able to make metabolizes on their own. Viruses are often found in prokaryotic and the eukaryotic cell, which can cause diseases.

Animal Parasites

A eukaryotic group comprised of flatworms and roundworms. They are called the Helminths. Although they aren’t microorganisms by definition, as they are big enough to be observed by eyes that are not blind, they do live in a portion of their cycle in microscopic forms. Because parasitic helminths are significant in clinical terms they are often studied along with other microbes.

Types of Microorganisms and Their Characteristics

5 Types of Microorganisms:  This tree of life shows the different types of microorganisms. Image Source:

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