What is the Difference Between Eukaryotic and Prokaryotic Flagella

The main difference between eukaryotic and prokaryotic flagella is that eukaryotic flagella are microtubule-based structures attached to the cell at the cell membrane through basal bodies, whereas prokaryotic flagella are located outside of the plasma membrane.

Eukaryotic flagella and prokaryotic flagella are two types of hair-like structures that protrude from cells. Their main function is to provide motility to the cells. Some organisms have single flagella while others have multiple flagella.

Key Areas Covered

1. What are Eukaryotic Flagella
   • Definition, Structure, Function
2. What are Prokaryotic Flagella
   • Definition, Structure, Function
3. Similarities Between Eukaryotic and Prokaryotic Flagella
   • Outline of Common Features
4. Difference Between Eukaryotic and Prokaryotic Flagella
   • Comparison of Key Differences

Key Terms

Flagella, Eukaryotic Flagella, Prokaryotic Flagella

What are Eukaryotic Flagella

Eukaryotic flagella are the type of flagella that occur in animal, plant, and protist cells. They are complex cellular projections that lash back and forth. In general, the structure of the eukaryotic flagella is similar to the motile cilia that occur in mammalian cells. However, the length, waveforms, and function of the eukaryotic flagella are different. Structure-wise, the core of the eukaryotic flagella is an axoneme. It is a bundle of nine fused pairs of microtubules known as doublets, surrounding two central single microtubules (singlets). Therefore, this structure is called a 9+2 axoneme.   

Figure 1: Eukaryotic Flagella

Furthermore, the 9+2 axoneme structure is characteristic of the eukaryotic flagellum. In addition, the base of the flagellum is the basal body, which is structurally similar to the centriole. The plasma membrane encases the flagellum. In addition, the main function of the eukaryotic flagella is to run a bending movement.       

What are Prokaryotic Flagella

Prokaryotic flagella are helical filaments with a rotary motor having the ability to turn clockwise and counterclockwise. The main function of prokaryotic flagella is the motility of the bacterial cell. Normally, the protein subunits of the bacterial flagellum are flagellin subunits. The bacterial flagellum is a 20 nm thick and hollow tube. Significantly, it has a sharp bend just outside the outer membrane, forming a hook. The hook contains a shaft that runs to the basal body.

Figure 2: Eukaryotic and Prokaryotic Flagella

Moreover, Gram-positive bacteria contain two basal body rings, one in the peptidoglycan layer and the other in the plasma membrane. In contrast, Gram-negative organisms have four basal body rings associated with lipopolysaccharides, peptidoglycan layer, embedded in the plasma membrane, and directly attached to the plasma membrane.

Similarities Between Eukaryotic and Prokaryotic Flagella

• Eukaryotic and prokaryotic flagella are two types of flagella that protrude from cells.
• Their main function is to undergo cell motility.
• They are made up of proteins.

Difference Between Eukaryotic and Prokaryotic Flagella

Definition

Eukaryotic flagella refer to complex cellular projections that lash back and forth, occurring in animals, plants, and protists, while prokaryotic flagella refer to helical filaments, each with a rotary motor at its base which can turn clockwise or counterclockwise.

Movement

Eukaryotic flagella have a bending movement while prokaryotic flagella have a rotary movement.

Type of Proteins

Eukaryotic flagella contain tubulin proteins while prokaryotic flagella contain flagellin protein.

Size

Moreover, eukaryotic flagella are large and thick while prokaryotic flagella are small and thin.

Presence of Microtubules

Eukaryotic flagella contain microtubules while prokaryotic flagella do not contain microtubules.

Structure

While eukaryotic flagella contain a complex, sliding filament system, prokaryotic flagella contain a rotary motor.

Components

Eukaryotic flagella are microtubule-based structures, which are attached to the cell at the cell membrane through basal bodies, while prokaryotic flagella are located outside of the plasma membrane.

Membranous Sheath

Eukaryotic flagella contain a membranous sheath while prokaryotic flagella do not contain a membranous sheath.

Conclusion

In brief, eukaryotic flagella and prokaryotic flagella are two types of hair-like structures important in the motility of the cells. Usually, eukaryotic flagella contain microtubules while prokaryotic flagella do not contain microtubules. Eukaryotic flagella show a bending movement while prokaryotic flagella show a rotary movement. Normally, tubulin is the protein that occurs in the eukaryotic flagella while flagellin is the protein that occurs in the prokaryotic flagella. However, the main difference between eukaryotic flagella and prokaryotic flagella is their structure and the type of movement.

References:

1. Wikimedia Foundation. (2022, August 17). Flagellum. Wikipedia. Retrieved September 27, 2022.

Image Courtesy:

1. “Eukarya Flagella” By Franciscosp2 – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Difference Between Prokaryote and Eukaryote Flagella” By Mgaetani – Own Work (CC BY-SA 4.0) via Commons Wikimedia