hello everyone what do we see here well that's a sperm moving do you have any idea which structure is helping in its movement that structure which is rotating yes it's the fagula so today we are going to learn about Celia and fagela that helps in movement in different kinds of cells Celia and filla are kinds of cytoplasmic projections that are present in different kinds of cells and help help mostly in movement of the cell itself or other substances in contact with the cell for example a long fagella which is usually a single or a tough of elongated tibular structures help in Locomotion in case of bacteria in case of sperm cells in case of some motile spores or gamuts in case of plants and animals whereas very small hairlike projections called Celia are usually present all over the cell surface and can help in movement of substances that it comes in contact with let me give you an example inside our respiratory tract and inside the fallopian tube of the females there are cells which are provided with Celia these are cated epithelial cells so whenever in a tibular organ the inner lining is surrounded by cells provided with Celia these Celia they carry out a certain kind of movement that helps in substances to pass through the tube so Celia and filla they have similar structure however the Celia are much smaller in size and usually many present all over the cells like we see in case of paramecium and flatula usually usually is a very elongated structure whip-like structure which which helps in Locomotion for example in case of sperm cells and in case of bacteria fagela in case of procaryotic cells and that in case of eukaryotic cells they differ in their structure so in case of procaryotic cells the Fela is made up of feline proteins whereas in eukaryotic cells the Fela has a particular arrangement of a specific type of protein called tubulin however the structure of Celia and Fela Remains the Same so the first part of the structure of a fagula is the base with which it remains attached to the cell membrane and cytoplasm and that is known as the basil body or the blepharoplast the basal body of Celia and fella has a structure extremely similar to that of cental what does that mean it means that it has nine Triplets of microtubules arranged in a circle and at the center there are no micro tubules so this is known as the 9 plus zero arrangement for details you can refer to the structure of the centrioles the Basel body was present from the cell membrane embedded in the cytoplasm now inside the cytoplasm to give this flagella a little more support and strength there are fibrillar structures called rootlets with which anchor into the cytoplasm and provide support and Anchorage to the entire fagula the basil plate is present just above the basil body that is towards the exterior of the cell so we have rootlets then basil body then basil plate now at this point there is a structural change that takes place in the entire protein Arrangement so in the basil body we had a cylinder made up of of nine Triplets of micr tibul so there were nine groups of microscopic proteinous tubules arranged and each group consisted of three microscopic proteinous tubules but from the base plate out of these three one microscopic tibule stops uh elongating and now from here the entire structure is made up of nine groups of Duets that is nine groups of microtubules where each group consists of two microtubular structure the shaft or the actual part of the fagula that is visible to us is made up of a specific arrangement of microtubules so first let me describe what is a microt tibule you see tibin proteins are arranged in an elongated pattern one beside the other two types of tubulin proteins A and B remain arranged in an elongated Manner and if you see in cross-section you can see two tibul proteins in cross-section so this forms a couple or a pair of tribulin protein we call it a dublet now the entire filla if you see in cross-section what is its shape it is cylind rcal so the exterior of the cylindrical the the periphery of the cylinder is made up of nine doublets arranged in a circle what does that mean two types of tubulin protein A and B forms a pair and there are nine such pairs as shown here to form the peripheral circle now at the center there are two tubulin proteins forming the central core or the central Hub so you have nine plus at the center two two Arrangement this is called the 9 + 2 arrangement of microtubules now you have to keep the microtubules attached to each other at the same time you have to keep the microtubules attached to the central Hub so that they don't disperse this creates a cart wheel model now let's see what a cart wheel looks like or what the model looks like so from every a subunit proteinous hooks appear from A subunit and B subunit two proteinous hooks appear which are made up of dying proteins and they have atps activity so from one couple of A and B micr tibule the D protein projects and attaches to the B subunit of the next couple and then it can use ATP to allow some movement this helps the entire flagel periphery to move so the entire Flaga can move you also have to keep the center attached to the peripheral microtubules so from the center nine spokes appear like the spokes of the wheel that keep the center attached to the peripheral doublets to keep the doublets connected with each other there's another kind of protein called the NEX Sy protein also known as the Linker it keeps the B subunit of one couet connected with the a subunit of the next one so that this entire periphery made up of proteinous subunits can remain as an intact layer and not disperse so as we can understand the structure of the fular shaft is made up of tibin proteins that are arranged in nine plus two Arrangement two subunits at the center and nine doublets surrounding the center which forms the flagel shaft now this entire shaft remains surrounded by or covered by the cell membrane except possibly the last portion in case of sperm cell the last portion is without the cell membrane it can also have the cell membrane in certain cells so are there any differences between Celia and fagela well structurally not much but yes in case of Celia they are much smaller in size flagella they are much longer whip likee Celia usually are present like hair or hairlike projections or bristles all over the surface of the cell Flaga usually located in certain regions fagula shows undulating motion which is kind of a rotatory motion whereas Celia shows pendular motion which is moving in One Direction C IA is usually responsible for movement for feeding for Iration Etc fagula is essentially for movement so these are the basic differences between Celia and flagella so all these Celia and filla they require certain kind of stimuli so that they can beat let me ask you a question can you find out what is the stimulus for the Fela of the sperm cell to move where does it get its energy from is there any external Factor increasing the flagel movement please find out and let me know in the comments below I wait eagerly to look at your answers hope you enjoyed the video and you learned from it do hit the like button and share it with your friends if you did if you haven't subscribed to our YouTube channel yet please hit the Subscribe button right now and click on the notification Bell do check out the full courses on our website and Android App manocha Academy links are all given below so let's stay connected and let's keep learning together