In this video we're going to introduce pillai. And so the surface of bacterial cells can have relatively long filament, tous protein structures that are called pillai. And so pillai is actually the plural form of the word. The singular form is pitiless. And so these pillai are protein filaments that extend from the surface of the cell and these extensions can have varied functions. And so if we take a look at this image down below, notice that we're showing you a bacterial cell right here and extending off is this long filaments protein structure that we call a pitiless. And the pillows can have varied functions depending on the cell type. And so we'll get to talk about some of the main types of functions of pillai in our next lesson video. So I'll see you all there.
Functions of Pili
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in this video, we're going to talk about some of the functions of pillai. And so pill I typically number and only 1- Pillai Purcell. And although pill I can have many different functions generally pill I have two primary functions that we have number down below one and two. And so the first primary function of pillai is cell motility and motility is really just referring to the ability of an organism to move through its environment. And so you can see that in this image uh the bacterial cell here is using its pillows to move from the starting point to the finish line over here. And so pill I can be used for cell motility for a cell to propel itself and move itself through its environment. Now the second primary function of pill I'd is for D. N. A. Transfer. And so the pillows can be used as somewhat of a bridge to connect one cell to a neighboring cell. And this pillows can be used as a bridge or a tunnel to transfer DNA from one cell and transfer that DNA to a neighboring cells so you can see here that the D. N. A. Is almost like a gift. And uh bacterial cells are able to exchange DNA with neighboring cells by using their pillai. And so this is something that will be able to talk more about as we move forward in our course. But for now this year concludes our brief introduction to the functions of pillai. And so I'll see you all in our next video.
Which of these are true about pili?
Pili are short filaments of pilin on the surface of bacterial cells that allow neighboring cells to adhere to one another.
Pili allow cells to “crawl” across a surface.
Pili are short filaments on the surface of archaea cells that allow neighboring cells to adhere to one another.
Pili allow cells to share genetic information through a process called DNA transfer or conjugation.
A and B
B and C
A and C
B and D
Cell Motility by Pili
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in this video, we're going to talk about how pill I can be used for cell motility or sell movement. And so pillai are actually involved in two types of cell motility that we have number down below one and two. And so the first type of cell motility that pillai are involved in is twitchy motility. And so twitching motility is can be described as the pill i itself extending from the cell attaching to a surface and then retracting in order to drag the cell forward. And so during the retraction period the cell is actually moving towards its destination and a twitching like or a jerking like motion. And so this is where it gets its name from the twitching motility. And so if we take a look at our image down below, at the twitching motility right here, notice that with this the bacteria is going to be extending its pillows attaching its pillows to an area that's further along the destination, and then retracting its pillows in order to pull the bacterial cell forwards in the direction of its movement. And so it is going to be a twerking or a jerking type of movement that is not going to be continuous and it's going to appear very twitch like uh type of motion. Uh Now on the other hand, the second type of motility that pillai are involved in is gliding motility and and gliding motility. There is going to be a smooth movement that is not going to have a twitch like or a jerk like effect. And so there's the movement will be smooth along um The movement of the cell along the axis will be smooth. Now there are motor proteins that are involved with this process that will attach the surface surrounding the cell, but the exact mechanism of this is unknown. And so if we take a look at our image down below, at the gliding motility, which will notice, is that there are motor proteins that are involved in the pill. I is also going to be involved in some way, but ultimately, the cell movement is going to be very smooth and it is not going to be twitch like. And so you can see we have the motor proteins that are labeled here. And so really the big difference is that the twitching motility and the gliding motility both somehow involved a pill. I uh and the twitching motility is going to be in twitch like or jerk like fashion, whereas the gliding motility is going to be in a smooth like fashion. And so this year concludes our brief introduction to cell motility by pillai and we'll be able to get some practice as we move forward. So I'll see you all in our next video
________ is the mechanism where a bacterial cell uses its pili to crawl across a surface towards a destination:
None of the above
Scientists believe some bacteria are able to “glide” through their environment by…
Attaching their pilus to a surface and pulling the cell towards the destination.
Moving their flagella back and forth allowing them to swim towards the destination.
Using motor proteins on the cell’s surface to spin the cell along an axis towards the destination.
Which cellular structures are involved in conjugation?
All of the above
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in this video, we're going to introduce the sex pitiless. And so the sex pill is is also referred to as the conjugation pitiless and what it does is it connects to cells directly for a special type of DNA transfer known as conjugation. And so conjugation can be defined as the process by which DNA is transferred or the process of transferring DNA directly from one bacterial cell to another bacterial cell by using direct contact through the sex palace or the conjugation pitiless. Now this transfer DNA that occurs via conjugation can actually add a new function to a cell, for example, resistance to antibiotics. And so if we take a look at this image down below, we can get a better understanding of how a sex pills can bring to cells together to directly transfer genetic material from one cell to another cell. And so notice over here in this part of the image that we're showing you to bacterial cells. Bacterial cell A is over here and bacterial cell B is over here and notice that bacterial cell A. Has this little yellow circle here which is representing A. D. N. A. Plasma. And it has uh some uh perhaps antibiotic resistance on this plasma. And so bacterial CELL A. Has the plasma and is resistant to antibiotics. But notice that Selby over here does not have that little yellow circle and so it is going to not be resistant to antibiotics. It will be sensitive to antibiotics. However, through this green structure that you see here, which is the sex pitiless itself or the conjugation pitiless uh what can happen is that the sex pills can help to bring the two cells into closer proximity, move the two cells together. So notice that the movement of the cells is towards each other because of the actions of the sex pills. And so the sex pills can help with this process of congregation to transfer this DNA plasma over to the other cell. And so that's what we see over here in this image is the D. N. A. Is actually being copied and transferred over to Selby. And so you can see here that the D. N. A. Plasma is being replicated and being copied and transferred over to Selby. And in the end over here, notice that we have Cell A. And Selby. Both have that plasma so that D. N. A. Has been transferred from Cell A over to Selby through the action of the sex pillows. And notice that both sell A. And Selby each have their own sex pillows. And so now Selby can move on to transfer its D. N. A. To another cell that may not have it. And so this is through the action of the sex pillows or conjugation pillows. And this concludes our lesson here. So, I'll see you all in our next video.