Difference Between Cilia And Flagella

Cilia and flagella are cell organelles having similar structure but differ in their function and length. Cilia are short in size and are present in large number in the cell. On the other side, flagella are longer in size and are few per cell. Learn the difference between cilia and flagella here.

Cilia has slender, microscopic, short hair like structure whereas flagella have long hair like filamentous cytoplasmic complex structure. Both are the most common organelles and have locomotive structures. They are found in unicellular organisms. They also help in processes like respiration, circulation, excretion, etc.

Cilia and flagella are found in eukaryotic cells whereas, flagella are also present in prokaryotic cells. Cilia are found in paramecium organism and flagella are present in bacteria and sperm cells.

Let us discuss the key differences between these two structures.

Difference Between Cilia And Flagella

Character	Cilia	Flagella
Definition	Cilia are short, hair like cell organelle extending from the surface of a living cell.	Flagella are long, threadlike cell organelle present on the surface of a living cell.
Found in	It is found in Eukaryotic cell.	It is found in Prokaryotic cell as well as in eukaryotic cells.
Length	Cilia is short and hair like organelle (5-10µ) in length.	Flagella is long wipe like organelle (150µ) in length.
Thickness	Cilia is around 0.3 to 0.5 um thick.	Flagella is around 0.02 to 0.025 um thin.
Position	It is present throughout the surface of cell.	It is present at both the ends or all over the surface.
Density	It is present in many (hundreds) per cell.	It is present in few (less than 10) per cell.
Motion	The motion of cilia is rotational, very fast moving.	The motion of flagella is rotary movement in prokaryotes whereas it is bending movement in eukaryotes.
Beating	Cilia beat in coordination or one after the other.	Flagella beat independent of each other.
Functions	It helps in locomotion, aeration, feeding circulation, etc.	It helps mainly in locomotion only.
Examples	It is present in Paramecium.	It is present in Salmonella.

Cilia

Cilia are short, slender, hair-like organelle extending from the surface of the living cell. It is most active during cell cycle progression and growth. The width of the cilium is around 0.3 to 0.5 um, and the length is 5-10µ.

Cilia are found in almost all eukaryotic cells. Cilia help in the overall development of the body and functions in a cell. It is further divided into two types, Motile and Non-Motile Cilia.

Types of Cilia

Motile Cilia

Motile or moving cilia are mainly present in the middle ear, lungs, and respiratory region. The main function is to keep the airways clear of mucus and dust, this helps to breathe freely, without any irritation. They also help in the movement of the sperm whereas, in female mammals, the beating of cilia in the uterine tubes moves the ovum from the ovary to the uterus.

Non-Motile Cilia

Non-motile or primary cilia are mainly present in nearly every cell in all mammals and they do not beat. It can be found in human sensory organs such as the eye and the nose. The main function is to receive signals from other cells by acting as the receiver for the cell.

For example in the kidney, it send signals to the cells about the flow of urine. Even in the eye, it helps in the passage of molecules from one end of the photoreceptor of the retina to the other.

Flagella

Flagella are the complex, hair-like filamentous cytoplasmic complex structure, present on the surface of the cell. It is mainly responsible for motility. It long wipes like organelle (150µ) in length and around 0.02 to 0.025 um thin. Flagella are composed of protein like flagellin, fixed in the cell envelope. Flagella are of three types – bacterial flagella, archaeal flagella, eukaryotic flagella.

Types of Flagella

Bacterial Flagella

Bacterial flagella are found in Salmonella typhi, E. coli. They have a helical filamentous structure that rotates like screws. These provide motility to bacteria. The motion is rotary movement in prokaryotes. This flagellum can be one, two, or many per cell.

Archaeal flagella are similar to that of bacterial flagella. The only difference is that archaeal flagella lack in the central channel as compared to bacterial flagella.

Eukaryotic flagella are the complex projections, that beat from one place to another and then return to the first location, often over and over again. The best example is the sperm cell, which moves through the female reproductive region by using its flagellum.

Reference

https://en.wikipedia.org/wiki/Cilium

https://en.wikipedia.org/wiki/Flagellum