Cilia and Flagella share some similarities but there are differences between the two. In this article, I hope to give you a quick overview of these and help you to better understand both organelles and recognize what is different between them.
What are Cilia And Flagella?
Both Cilia and Flagella are the most common organelles for locomotion in unicellular organisms.
Now in layman’s terms, this essentially means that they create currents in their surroundings which help to move a cell in one way or another. So basically it’s the Cilia and Flagella’s job to move the cells.
Structurally the pair are both fairly similar, but they differ in both their length and their function.
For example, Cilia is more present in organisms such as Paramecium whereas Flagella can be found in bacteria and sperm cells.
So now we know exactly what they are. Let’s take a look at what makes them different.
Cilia are slender protuberances that come out from the much bigger cell body. They are described as short and look a little bit like fine hair sticking out from the surface of a cell.
Flagella is more of a lash-like extremity that protrudes from the cell body. They are described as long and thread-like appendages that are on the surface of the cell.
Cilia is usually shorter out of the two in length. Exactly how Cilia is measured in length can get a little bit confusing so I’m not going to go into how exactly this measurement comes about but know that Cilia is usually around 5-10µ.
Flagella is much larger than Cilia in length. It measures at about 150µ which as you can see is a considerable jump from Cilias 5-10µ.
Number Of Organelles
Compared to Flagella there is a much higher count of Cilia. Typically Cilia ranges in the thousands.
Flagella have considerably less in number. You are usually looking at a range of just one to eight.
The beating system of Cilia is much more complex than that of Flagella as it can move in a much wider range of motions. Cilia beat in a coordinated rhythm.
They can do this either simultaneously which is known as being synchronous, or independently which is known as being metachronous.
Flagella does not share this in common with Cilia as they beat independently from each other. This involves a circular motion that can also be described as wave or propeller-like.
Cilia move in a much faster motion than Flagella. It rotates a bit like a motor would.
As mentioned above, Flagella’s motion is more wave-like. This undulating motion is a much slower movement than that of Cilia.
Cilia will be found in Eukaryotic cells. What is an Eukaryotic cell? Technically speaking, it’s single celled or multicellular organisms who’s cells contain a distinct membrane bound nucleus. So for example, animals, plants, and fungi have eukaryotic cells.
Flagella can also be found in Eukaryotic cells. However unlike Cilia, it can also be found in Prokaryotic cells. What are Prokaryotic cells? Prokaryotic cells are in the domain of Eubacteria and Archaea.
What this basically means is that Flagella can be found in bacteria and blue-green algae.
Cilia use something called ‘Kinesin.’ This has an ATPase activity which produces energy which makes it possible to create movement.
Flagella, however, are powered by a proton-motive force produced by the plasma membrane.
Really, the difference between Cilia and Flagella can be quite obvious, and so it shouldn’t be too difficult to recognize them individually. They are both quite different in appearance as well as their movement.