Eukaryotic cilia and flagella are essential for cell motility, composed of microtubules arranged in a 9 + 2 structure. Cilia function like oars, moving objects around or propelling the cell, while flagella exhibit a whip-like motion for propulsion, powered by ATP hydrolysis. Understanding their structure and function is crucial for grasping cellular movement mechanisms in eukaryotic organisms.
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concept
Eukaryotic Cilia & Flagella
Video duration:
2m
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Video transcript
In this video, we're going to begin our lesson on eukaryotic cilia and flagella. The cytoskeleton, specifically microtubules, is a major structural component of both cilia and flagella. Both are important for providing cell movement. They also extend outwards from the cell surface and are anchored to the cell by a basal body. Cilia are short, hair-like structures covering the cell, while flagella are longer, tail-like structures that can be distributed in different ways. Both cilia and flagella are made up of long microtubules that are together in a 9+2 arrangement. This 9+2 arrangement refers to the fact that there are nine pairs of microtubules surrounding two central microtubules.
Notice in the image on the left-hand side, we are showing cilia, which are these short hair-like projections sticking off the surface of the cell. We're also showing flagella, which are longer tail-like structures. You can see, zooming into the structure, a 9+2 arrangement, which again refers to the fact that there are nine pairs of microtubules surrounding two central microtubules. These microtubules project throughout the entire structure, downwards, as seen in a bird's eye view at the very top of the cilia or flagella. This concludes our brief introduction to eukaryotic cilia and flagella, and we'll get some practice applying these concepts as we move forward. I'll see you all in our next video.
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Problem
Problem
Eukaryotic cilia & flagella are made of:
A
Intermediate filaments
B
Microtubules
C
Chitin
D
Phospholipids
E
Cellulose
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Problem
Problem
What does the 9 + 2 arrangement of microtubules refer to in structures of cilia and flagella?
A
The microtubules' length.
B
The microtubules' association with the basal body.
C
The microtubules' arrangement in the axoneme.
D
The microtubules' arrangement embedded in the cytoplasmic membrane.
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concept
Eukaryotic Cilia & Flagella Motility
Video duration:
1m
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Video transcript
This video, we're going to talk about the motility of eukaryotic cilia and eukaryotic flagella. And so again, motility is referring to the ability to be able to move and cause movement. And so cilia and flagella have similar overall structure, but each is associated with a different type of cell movement. And so cilia are actually going to be associated with a movement that is similar to the movement of oars like boat oars. And so they are going to move objects around the cell or they are going to provide cell movement for the cell itself. Now flagella, on the other hand, do not move like oars. Instead, they move in somewhat of a whip-like fashion. And so they are going to be propelling the cell through its environment, and that propulsion is going to be powered by ATP hydrolysis rather than being powered by a proton motive force or a PMF like what prokaryotic flagella are powered by. And so, if we take a look at this image down below, notice on the left hand side, we're showing you the oar-like motion of the ciliate. And so it's going to be moving somewhat like an oar where it goes in this direction, it comes back, and continuously moves like an oar. Now the flagella, on the other hand, which you can see over here, are going to be moving in more of a whip-like fashion. And so that whip-like fashion is going to help propel the cell through its environment. And so this here concludes our brief introduction to the motility of eukaryotic cilia and flagella. And we'll be able to get some practice applying these concepts as we move forward. So, I'll see you all in our next video.
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Problem
Problem
Which of the following is not true regarding cilia and flagella?
A
Both cilia and flagella can provide a form of locomotion for the cell.
B
Cilia are shorter and more 'hair-like' while flagella are longer and more 'tail-like'.
C
Cilia move with a 'whip-like' motion while flagella move like 'oars' to propel the cell.
D
Cilia can cover the entire cell's surface while flagella are usually few in number and only at one end of the cell.
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