Types of Bacteria - EP2
2 Minutes
Types of bacteria for kids: learn how bacteria are classified by their flagella and how they breathe. A short science lesson in English.
- How bacteria use flagella to move around like a tail
- Five flagella types including monotrichous and peritrichous
- Aerobic and anaerobic bacteria that breathe with or without oxygen
What this lesson teaches
Bacteria can be classified by the number and arrangement of their tail-like flagella, as well as by the way they breathe. These physical structures and life processes allow scientists to group different species based on how they move through their surroundings and whether they require oxygen to survive.
How bacteria move using flagella
Just like monkeys have tails and humans use legs to walk, bacteria rely on tail-like structures called flagella to move around. The word trichous refers to this hair-like tail structure. While bacteria are also classified by shapes such as rod-shaped, spherical, spiral-shaped, and comma-shaped forms, looking at how flagella are positioned divides bacteria into five specific groups.
Five types of flagella arrangements
- Monotrichous bacteria have a single flagellum at one end, where mono means single, as seen in the bacterium Vibrio cholerae.
- Lophotrichous bacteria have a cluster of many flagella grouped together at only one end, such as the bacterium Pseudomonas.
- Amphitrichous bacteria have several flagella situated at both ends of the cell, such as the bacterium Rhodospirillum rubrum.
- Peritrichous bacteria have flagella covering the surface of their entire body, with Escherichia coli being a clear example.
- Atrichous bacteria completely lack flagella because the letter a means absent, as seen in the bacterium Corynebacterium diphtheriae.
How bacteria breathe
Bacteria are also grouped according to the way they breathe. Humans breathe by taking in oxygen from the surrounding air, and any bacteria that breathe using oxygen are known as aerobic bacteria. However, some bacteria are capable of breathing even when there is no oxygen present at all. Bacteria that breathe without oxygen are known as anaerobic bacteria.
Respiration types and examples
- Mycobacterium tuberculosis is an aerobic bacterium that breathes by using oxygen from the air just like humans do.
- Escherichia coli is an anaerobic bacterium that can carry out its breathing without needing any oxygen.
- The lesson shows that Escherichia coli can be identified in two different ways, as a peritrichous bacterium by its flagella and as an anaerobic bacterium by its respiration.