Flagellum facts for kids

Difference of beating pattern of flagellum and cilia. Flagellum is the one on the left, cilia are on the right.

A flagellum (plural: flagella) is a long, thin part that sticks out from some cells. It looks a bit like a whip or a tail. Its main job is to help tiny living things, like bacteria or single-celled organisms, move around.

Flagella are made of tiny tubes called microtubules. They push the cell forward with a waving or spinning motion. Think of it like a tiny motor or propeller for a cell!

These structures are very similar to Cilia, which are usually shorter and more numerous. Both flagella and cilia are special parts of a cell, called organelles. Organelles are like tiny organs within a cell, each with a specific job. Other organelles you might know are mitochondria (which make energy) or plastids (found in plants).

Scientists believe that many organelles, including flagella and cilia, might have once been independent tiny organisms themselves. Over a very long time, they started living inside other cells. This created the complex cells we see today, like those in plants and animals. It's like a team of tiny helpers working together!

What are the Types of Flagella?

There are three main types of flagella, found in different kinds of living things. These types are bacterial, archaeal, and eukaryotic flagella. They all help with movement, but they work in slightly different ways.

• Bacterial Flagella: These are found in bacteria. They are shaped like a spiral and spin around like a screw. This spinning motion helps bacteria swim through liquids.
• Archaeal Flagella: These are found in archaea, which are another type of tiny, single-celled organism. They look a bit like bacterial flagella on the outside. However, they are built differently on the inside and work in their own unique way.
• Eukaryotic Flagella: These are found in more complex cells, like those of animals, plants, and protists (single-celled organisms that are not bacteria or archaea). Unlike bacterial flagella, eukaryotic flagella move with a back-and-forth lashing motion, like a whip.

Eukaryotic flagella and motile (moving) cilia are sometimes grouped together as undulipodia. This name highlights their wavy, tail-like role in helping cells move. Some cilia, called 'primary cilia', do not move. They have a different internal structure and are not used for swimming.

Images for kids

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  Different flagellar arrangements in bacteria

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  The "9+2" structure is visible in this cross-section micrograph of an axoneme.

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  Multiple flagella in lophotrichous arrrangement on surface of Helicobacter pylori

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  Physical model of a bacterial flagellum

See also

In Spanish: Flagelo (biología) para niños