26. Prokaryotes
Prokaryotic Reproduction
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this video we're going to begin our lesson on the mechanism of F plasmid conjugation in E coli. And so for the transfer of the F plasmid to occur from an F+ cell to an F minus cell, this actually involves a series of steps that we have numbered down below in this image. And so notice that this image is focusing on f plasmid conjugation. And in the very first step, the donor cell, which is the F plus cell, is going to contain the entire F plasmid allowing it to form an F pilus. And so the donor F plus cell is able to initiate conjugation with a recipient cell, which is the F minus cell. And so what you can see over here is we're saying that the F pilus of the F plus donor cell is going to bind to a receptor on the outer membrane of the F minus recipient cell. And so that's exactly what we can see taking place right here where the, F pilus of the donor F plus cell is going to bind, as you see here, to the outer membrane of the F minus recipient cell. Then in step number 2, what you're going to see is that the F pilus is going to, retract. And so when the F pilus retracts, it shortens and therefore it pulls the cells closer together. And so you can see here that the F pilus is retracting, represented by this backwards arrow, and the retraction of the pilus brings the 2 cells closer together, as you see here and here. And then, the f plasma itself is actually going to be cut at the oriT region of the f plasma. And so here what you can see is that the oriT region is indicated in red and the plasma is being nicked or cut right at that oriT region. And so what can happen at this point in step 3 is that just a single strand of the f plasmid is going to, enter the f minus cell. And then, that single strand is gonna be used as a template to replicate to replicate the f plasmid within the f minus cell. And so what you can see over here in this image is that the single strand of the F plasmid is going to enter into the F minus cell, but as it's entering, it's being replicated. And so you can see that, the yellow border here corresponds with the yellow replicate that you see here. And so, you can see that it is being replicated as it enters into the f minus cell. And so once the transfer of the entire F plasmid is complete, then what happens is both the donor and the recipient cell are going to be F plus cells because they each have a full copy of the F plasmid. And so you can see over here we have the donor F+ cell, still retains its, entire plasmid, and the recipient cell, is now F+ because it contains the entire F plasmid that was transferred once again from the F+ cell over to the Fminus cell. And so this is a big takeaway of, F plasmid conjugation is that both cells at the end of conjugation are going to be F+. And this is going to be different as we talk about other types of conjugation. So this is really important to keep in mind. And so this here concludes our brief introduction to the mechanism of F plasmid conjugation in E. Coli. And once again, we'll be able to get some practice applying these concepts and learn about other types of conjugation as we move forward in our course. So I'll see you all in our next video.
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