Review of Prokaryotic Surface Structures

in this video, we're going to begin our review of pro carry attic surface structures. And so in this video we're only going to be reviewing information that we've already covered in our previous lesson videos. And so if you're feeling really good about the information that we've covered, then feel free to skip this video. However, if you're looking for a little bit of extra help then stick around because this review video could be helpful for you. And so notice that we have this table down below of all of the different surface structures that we covered in our previous lesson videos. And so we're starting here with the Gleick okay Alex, which recalls the sticky gel like policy Sacco ride layer that surrounds cells. And so we call that the Glencoe kayla's comes in two forms, which is why we have this bracket here on these two roads. The first is the capsule which recall the capsule is a highly organized layer of poly sacha rides that is tightly anchored to the cell and so you can see the image that we use from our previous lesson videos to show the organization of the capsule. Now, the slime layer, on the other hand, is a form of look like okay Alex that is much less organized and so it's a less organized layer of poly sacha rides and it's going to be more loosely attached to the cell. And so you can see the less organized image of the slime layer that we used in our previous lesson videos. Next? What we have are the pill. I and so we said that the pill I are long protein filaments that extend from the surface of the cell and they can have varied functions. They can primarily serve as either for motility purposes, allowing for twitching, motility and gliding motility. Or they could serve as a sex pill is to allow for conjugation, which is basically the transfer of D. N. A. Through direct contact between bacterial cells. Next what we have are the fem bria, which recall that the february are short filaments that are going to be extending from the cells surface. And they're primarily going to be used for attachment purposes, allowing bacterial cells to attach to each other but also to attach to other surfaces as well. And so the february are going to be important for the formation of biofilms, which recall are these communities of microbes that live together within an extra cellular pollen merrick substance. Now next, what we have are the hammy and recall that the hammy are short protein filaments that are only found in our kale cells. And so this is specific only to the arcadia and so they act as short little grappling hooks that allow archaea to adhere to each other but also adhere to other bacteria and things of that nature. And then the last structure that we had talked about was the flow gela itself. And so the flow gela is a long protein filament that is going to be important for driving, swimming motility or uh the movement of cells in a run and tumble type of fashion. And so we have the structure and image representing the structure of the flow gela over here on the right. And so this here concludes our brief review of the pro carry attic surface structures. And in our next video, we'll be able to talk more about the flow gellar motility is that we talked about in our previous videos. So I'll see you all there.

in this video, we're going to review some of the different types of cell motility that we already covered in our previous lesson videos and so notice that we have this table that's down below. That's showing you the motility type, the structure that's being used and an image of the mechanism. And so first what we have is twitching motility, which recall is a type of motility that's going to be using the pill. I and so the pill I is going to be involved with extending out, attaching to the surface that's further ahead and then retracting in order to drag the self forward. And so this creates a twitching or a jerking type of movement, which is why it's called twitching motility. But pillai are going to be used for it. Now. The next type of motility that we have is gliding motility, which is also going to use pillai as well. And so the mechanism of this one is not as well understood, but it does involve the use of motor proteins and the pill I is also involved. But ultimately the cell is going to be moving in a more smooth fashion. And so you can see that the cell being able to move uh in a smooth fashion is why it's called gliding motility. And then last but not least, what we have here is swimming motility, which does not use pillai instead, it uses flow gela. And so the flow gela are able to rotate in a specific direction, such as counter clockwise to allow for runs and uh then rotate clockwise to tumble and it moves in a series of runs and tumbles. And recall the tumbles only allow for the change of direction, whereas the runs allow for a smooth swimming motion. And so this year concludes our brief review of the different types of cell motility, twitching and gliding use pillai, whereas swimming motility uses flow gela. And so 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.

Which prokaryotic cell surface structure is correctly matched with its function?

• A. Hami:Short protein filaments that hold bacterial cells together.
• B. Flagella:Long protein filaments that allow cells to swim.
• C. Fimbriae:Short pilin filaments which hold archaea cells together.
• D. Pili:Long filaments of pilin that are only used in DNA transfer between bacterial cells.