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Cilia and flagella are structurally identical cell organelles but differ in function and length. Cilia are small and abundant in the cell, measuring only a few millimeters in length. Flagella, on the other hand, are larger and more numerous organelles that are present in cells. In this article, we will discuss the difference between cilia and flagella.
| Table of Content |
Keyterms: Cilia, Flagella, Cell organelles, Cells, protozoans, eyelash, eukaryotic cells, phylum Ciliophora, vertebrates
Also Read:- Transportation in Animals and Plants
Cilia
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Cilia are small hair-like structures found on the surface of eukaryotic Cells that allow protozoans and animals to move around. The term cilia comes from the Latin word cilia, which means eyelash. It is named so because of its microscopic eyelash-like appearance.
Cilia are particularly prevalent in protozoans belonging to the phylum Ciliophora, which are known for having cilia. Ciliated cells can be found in a variety of tissues in complex creatures such as vertebrates, each with its own set of functions. Cilia move in a rhythmic pattern most of the time, and individual cilia do not move individually.

Cilia
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Types of Cilia
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Cilia are of two types: Non-motile and Motile.
- The motile cilia are present on the surface of cells in large numbers, and are most commonly found in the respiratory epithelium in humans.
- Non-motile cilia, on the other hand, serve as a sensory cellular antenna that communicates with a variety of cellular signalling pathways. They also alert the kidney cells, which aids in appropriate urine flow.
Flagella
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Flagella are long, hair-like projections that protrude from the plasma membrane and are utilized to propel a cell. Flagella moves around like eels. They produce waves that propagate down their length, usually at a constant amplitude from base to tip. They are utilized by cells such as the spermatozoon and Euglena to move about (protozoan).
They play an important function in eukaryotic reproduction and cell nutrition. They serve as propelling motors in prokaryotes, such as bacteria. It also gives pathogenic bacteria a way to help them colonize hosts and spread diseases. Flagella also serve as scaffolds or bridges for attachment to host tissue.

Flagella
Types of Flagella
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Monotrichous, lophotrichous, peritrichous, and amphitrichous are the four types of flagella.
- Monotrichous flagellums have a single flagellum on one end or the other. These may revolve both clockwise and anti-clockwise.
- The lophotrichous flagellums are those that are connected at one end or the other. They have the ability to rotate both clockwise and counterclockwise.
- The flagellums that are attached all around the creature are known as peritrichous. They are non-polar and can rotate in the opposite direction.
- The single flagellum linked to both ends of the organism is known as amphitrichous. They are polar and may rotate in both clockwise and anti-clockwise directions.
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Difference between Cilia and Flagella
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Flagella and cilia are cytoplasmic structures that extend from the cell surface. The cell organelles are similar in appearance but differ in size, number, function, and/or beating mode.
| Parameter | Cilia | Flagella |
|---|---|---|
| Definition | Cilia are hair-like appendages that emerge from a live cell's surface. | Flagella are long, threadlike extensions on a live cell's surface. |
| Located in | Eukaryotic cells | Eukaryotic and prokaryotic cells |
| Distribution | In the larvae of certain platyhelminthes, echinodermata, mollusks, and annelids, and in protozoans of the class ciliate and ciliated epithelium of the metazoan. | Protozoans of the Flagellata class, sponge choanocytes, metazoan spermatozoa, and algae and gamete cells are found in some bacterial cells. |
| Length | Shorter in length | Comparatively longer in length |
| Thickness | Have a larger diameter than flagella. They have a thickness of 0.3 to 0.5 um. | The flagella linked to the bacteria's border are 20-25 nm (0.02 to 0.025 um) thin. |
| Motion type | Rotational movement is highly quick. | In Prokaryotes, they have a rotary movement. In eukaryotes, they have bending movement. |
| Functions | Except for sperm, cilia are not used for locomotion in mammalian systems. | They are utilised to move in a complete cell and extend from the plasma membrane. |
| Examples | Cilia can be found in Paramecium. | Salmonella contains Flagella. |
Things to Remember
- Cells are the simplest and most basic unit of life.
- All living creatures and body tissues are made up of the cells that can live on their own.
- Cilia and flagella are structurally identical cell organelles that differ in length and function.
- Flagella can be found in bacteria and sperm cells, while cilia can be seen in species like Paramecium.
- Cilia are more numerous and shorter than flagella.
- Cilia and flagella come in a variety of shapes and sizes, and they serve a variety of purposes.
- Cilia are of two types i.e. motile and non-motile.
- Ciliated organisms move more quickly and efficiently.
- In unicellular organisms, the most frequent organelles for motility are cilia and flagella.
Previous Year Questions
- Cytoskeleton is made up of...[NEET 2009]
- DNA is not present in….[NEET 2015]
- Match the columns and identity the correct option...[NEET 1980]
- Experiments on Acetabularia by Hammerling proved the role of...[NEET 1992]
- Fluid mosaic model of cell membrane was put forward by...[NEET 1991]
- Identify the components labelled A, B, C and D in the diagram below from the list (i) to (viii) given along with Components:...[NEET 2010]
- The bacterial cell wall is made up of...[KEAM]
- Which of the following cell organelle is excluded from endomembrane system?..[KEAM]
- Choose the matched ones. (a)Vibrio Rod like bacteri (b) Mesosome...[KEAM]
- Consider the following statements. [KEAM]
- Identify the correct match between types of chromosomes and their descriptions...[KEAM]
- Fluid mosaic model was given by..[JIPMER 2015]
- Which of the following is correct regarding plasma membrane?..[JIPMER 2012]
- What are microsomes?[JIPMER 2012]
- The name sarcode was given to living substance of cell by...[JIPMER 2012]
Sample questions
Ques: What is the thickness of cilia? (1 Mark)
Ans: Cilia have a larger diameter than flagella. They have a thickness of 0.3 to 0.5 um.
Ques: What are different types of flagella? (1 Mark)
Ans: Bacterial flagella, archaeal flagella, and eukaryotic flagella are the three types of flagella.
Ques: What is the function of a polysome? (1 Mark)
Ans: Polyribosome or polysome is a chain-like structure that is formed when several ribosomes attach to a single mRNA . The ribosomes of a polysome convert the mRNA into proteins.
Ques: What is the feature of a metacentric chromosome? (1 Mark)
Ans: Metacentric chromosomes are V-shaped chromosomes. The metacentric chromosome has a middle centromere which forms two equal arms of the chromosome.
Ques: What is a satellite chromosome? (1 Mark)
Ans: Small fragments that emerge on chromosomes having non-staining secondary constrictions at a constant location are called the satellite or trabant chromosomes. Nucleolus is also formed by the satellite chromosomes.
Ques: Discuss briefly the role of nucleolus in the cells actively involved in protein synthesis. (2 Marks)
Ans: Nucleolus is a location at which active ribosomal RNA synthesis. Larger and more numerous nucleoli that are present in cells actively carry out the process of protein synthesis.
Ques: Explain the association of carbohydrate to the plasma membrane and its significance. (2 Marks)
Ans: Glycoproteins and glycolipids are the biochemicals that are involved in the process of cell recognition and adhesion. Glycoproteins and glycolipids are formed by Carbohydrates through glycosylation.
Ques: Where are Cilia and Flagella found? (2 Marks)
Ans: The motile cilia are found on the epithelial cells of the trachea, lungs, digestive system, and other internal organs. They are also present on protozoans like the paramecium, and they help these creatures move around. The non-motile cilia are mostly present in the olfactory neuron's dendritic knob. Flagella, on the other hand, are present on the underside of the cell or organism and, due to their whip-like structure they aid in smooth travel through liquids.
Ques: (i) Describe type of motion in cilia and flagella?
(ii) Differentiate between cilia and flagella on the basis of their length. (2 Marks)
Ans: (i) Motion of Cilia- Cilia have rotational movement that is very quick, similar to that of a motor.
Motion of flagella- In Prokaryotes, flagella have a rotary movement and in eukaryotes, they have a bending movement.
(ii) Cilia are 5-10µ long and flagella are 150µ long.
Ques: Write the functions of the following: (5 Marks)
(a) Centromere
(b) Cell wall
(c) Smooth ER
(d) Golgi Apparatus
(e) Centrioles
Ans: (a) Centromere: Every chromosome has a centromere. At the centromere, two sister chromatids are joined together.
(b) Cell wall: Cell wall protects the cell from mechanical damage and infection. It also provides shape to the cell and helps in cell-to-cell interaction. It also acts as a barrier to undesirable macromolecules.
(c) Smooth ER: The synthesis of lipids takes place in smooth endoplasmic reticulum. In animal cells, steroidal hormones are synthesised in SER.
(d) Golgi Apparatus: Glycoproteins and glycolipids are formed at Golgi apparatus.
(e) Centrioles: The centrioles form the basal body of cilia or flagella, and spindle fibres. These further give rise to spindle apparatus during cell division in animal cells.
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