In this video, we're going to introduce the sex pilus. And so the sex pilus is also referred to as the conjugation pilus. And what it does is it connects two 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 pilus or the conjugation pilus. Now this transferred 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 pilus can bring two 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 two 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 DNA plasmid.

And it has, some, perhaps antibiotic resistance on this plasmid. And so bacterial cell A has the plasmid and is resistant to antibiotics. But notice that cell B 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 pilus itself or the conjugation pilus, what can happen is that the sex pilus 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 pilus. And so, the sex pilus can help with this process of conjugation to transfer this DNA plasmid over to the other cell. And so that's what we see over here in this image is, the DNA is actually being copied and transferred over, to cell B. And so you can see here that the DNA plasmid is being replicated and being copied and transferred over to cell B.

And in the end over here, notice that we have cell A and cell B both have that plasmid. So that DNA has been transferred from cell A over to cell B, through the action of the sex pilus. And notice that both cell A and cell B each have their own sex pilus, and so now cell B can move on to transfer its DNA to another cell that may not have it. And so this is through the action of the sex pilus or conjugation pilus. And this concludes our lesson here, so I'll see you all in our next video.