For bacteria that are F⁺, Hfr, F', and F⁻ perform or answer the f...

Question

For bacteria that are F⁺, Hfr, F', and F⁻ perform or answer the following.

Which of these donors can convert exconjugants to a donor state?

Accepted Answer

Hi, everyone. Welcome back. Let's look at our next problem. It says blank cells have the ability to transfer donor genes to a recipient during conjugation. And our answer choices are A F minus B F plus C F prime or DH F R. Well, to think this through, it's useful to kind of think about each of these four types of cells and remember the distinctions between them. So we'll start with F minus cells which are cells that have no F factor. So we can go ahead and eliminate them because they don't have anything to transfer. So we'll cross out choice. A then next, we have our F plus cells which have the F factor as a separate plasmid. So that's a good candidate, but we've got some other cell types here. So let's keep going the H F R cells I list next because they have the F factor. But instead of being separate, it's now integrated into the bacterial chromosome. And then finally F prime cells. And at times when you have H F R cells that have this F factor integrated into the chromosomes, sometimes that F factor gets excised back out, becoming a separate plasma again. But when that excision happens, some neighboring genes come along with the F factor. So F prime cells have the F factor plus neighboring jeans from the bacterial chromosome as a separate plasmid. So it's sort of this journey here of our F factor. So we've got three types of cells that have the F factor that could be donated, but we have to pick the one that will just transfer donor genes. So the H F R cells have this F factor integrated into the chromosome. So it can transfer during conjugation, but it's not very efficient because as being integrated into the chromosome, it tends to get interrupted before all of the genes have been transcribed to be able to transfer it into the donor cell. So it tends to just transfer a portion of the F factor and genes into a donor cell. So that is why H F R is not what we're looking for. And then the F prime cells don't just transfer the F factor. They transfer also. So not just the little donor part, but they also transfer additional bacterial genes along with it. So we're gonna choose over F prime, we'll choose F plus because F plus just transfers donor genes by themselves that F factor and whatever is in that plasmid to the recipient. So F plus is the better choice than F prime in this case. So we will select, we're going to eliminate choice C F prime. We're going to select choice B F plus cells have the ability to transfer donor genes to a recipient during conjugation. See you in the next video.

For bacteria that are F⁺, Hfr, F', and F⁻ perform or answer the following. Which of these donors can convert exconjugants to a donor state?

Key Concepts

Conjugation in Bacteria

Fertility Factor (F Factor)

Hfr Strains

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