this next mechanism of introducing different genes to bacteria is transduction and transduction is the introduction of genetic material by way of a bacterio phase and a bacteria phase is a virus that is specific for bacteria and if you take a look at that bottom picture there is a picture of a bacteria phase to me it looks very robotic almost like it reminds me of those little hex toys that you might see at Target so it looks almost like out of this world and almost mechanical that is bacteria phase a bacteria phase would not affect our cells it would only affect bacteria and if you remember talking about the grand positive bacteria and we talked about that teic acid potentially it could be a docking station so that that bacteria phase can actually attack to that cell if viruses can't attach to the cell they're not going to be able to replicate so in order to really talk about Tre instuction we're going to have to talk about um a little bit about phases as well as the viral replication cycle remember viruses are not considered living things they are not cells they cannot undergo the characteristics of living things like metabolism maintaining homeostasis uh reproduction in fact we don't even say that viruses reproduce we usually say that they replicate they have to take over the hostel Machinery in order to replicate so they're what we would call obligate intracellular parasites so in order to really talk about how these phases introduce genetic material there's a couple of different types of phases um and there's a varient phase this is going to take over that cell machinery right away and it's going to cause Lis of the bacteria it's just going to kill it a temperate phase is almost like uh a more modified phase it's not going to cause death immediately and that phase DNA is actually going to be incorporated into that bacterial chromosome that's when we call it a proas and it's just going to kind of hang out there for many many generations it's not going to kill that cell right away bacteria has no idea that it's there so in order for these phases to kind of take over the cell and undergo replication there's a couple of different forms of viral replication and so I just want to introduce this a little bit we'll be talking a little bit more about this in chapter 11 on viruses so this is just a little introduction a little simplified View and these are the liic and and lysogenic cycle or liex cycle however it is that you prefer to say it so if you take a look at the left hand side this is a a snapshot of the liic cycle so there you can see that bacteria phase is attaching to the cell it's injecting its DNA and then it's taking over the hostel Machinery so that it can make its parts and then assemble the parts and then it blows open that cell lices that cell and now we've got all of these bacteria phases going out and they can infect other cells this is the violent quick cycle and that's going to take over the hostel Machinery right away and it's going to kill the cell lysogenic cycle is a little different this is the longer sneak year cycle as I call it so at that top picture on the right hand side you can see that bacteria phase attaching to the cell it's injecting its DNA but it doesn't take over the host cell Machinery right away you can see where it's incorporated into that bacterial chromosome this is when we call it a proas and it's just going to kind of hang out there for a while for many generations cell has absolutely no idea that that Viral DNA is incorporated into its chromosomal DNA so it's going to undergo many cell divisions until perhaps something happens in the environment maybe the cell is stressed out it's been exposed to chemical or radiation and that DNA is like whoa we are out of here and then it will actually cross over into the liic cycle now it's going to take over the hostel Machinery make its parts assemble its parts and then blow open the cell so these are two viral replication modes and so to really understand transduction we need a little preview of the liic and the lysogenic cycle so the two types of transduction that we'll talk about are generalized transduction and specialized transduction so with generalized transduction this is going to utilize that virulent phase that's the violent phase right so this is going to prompt it to go into the liic cycle so this is that quick cycle where it's going to take over the host cell machinery and blow open that cell so in this picture that I've drawn on the right we've got our bacteria phase with the red DNA that's the bacteria phase DNA and it's attached to the bacteria and you can see the blue circular chromosome so that varent phase is going to attach it's going to inject its DNA and then what you're not seeing from this picture is it's taking over the hostel Machinery to make its parts assemble the parts and then blow open the cell well that resulting bacteria phase if you look at the products down below some of them of those bacteria phase are packaged with the bacteria phase DNA and because this is kind of a messy chaotic cycle you'll notice that that one bacteria phase has the bacterial chromosomal DNA so it was actually packaged with that DNA in error so here's where the scrambling of genes comes in these bacteria phases can now go out and they can infect other cells so now another cell can actually have access to these genes so looking at that bacteria phase with the blue DNA with the bacterial DNA what if that was actually packaged with antibiotic resistant genes now a bacteria potentially could have access to those antibiotic resistant genes so a way to kind of scramble those genes so this is a case of generalized transduction and here's another picture where you can see that virulent phase and this is this picture is a little more detailed the DNA is injected it's going to take over the hostel Machinery so you can see where the parts are being made then they're being assembled and then they're being released if you notice in that second picture on the right hand side that b bacteria phase has the bacterial DNA in it and now if you can see with that picture now it's injecting that DNA into the cell you can see where that DNA is now incorporated into the genome now if that be DNA had an antibiotic resistant Gene now that bacteria has access to it so again another way to introduce genes and that genetic diversity the second type of transduction is specialized transduction this is when a temperate phase infects the cell and it's going to undergo the lysogenic cycle so in that picture we've got our bacteria phase and it's going to inject its DNA but it's not going to take over that host cell Machinery right away this is that longer sneakier cycle the lysogenic cycle that bacteria phase DNA is now going to become Incorporated in the bacterial genome and it's going to exist as a proas this bacteria has no idea that that DNA has been Incorporated it's going to go about its business and we're going to go through many many generations until something happens in the environment and then it crosses over to the liic cycle now that bacterial that phase DNA is going to take over the bacterial machinery and now it's going to make its parts assemble its parts so because that proas has been intermingling among that bacterial DNA some of that DNA is going to be combined with the bacterial DNA so if you take a look at the phase on the bottom you can see where it's a combination of the phase and bacterial DNA so they're almost like brand new phases so again incorporating those different genes and again here is another detailed picture where we're injecting that fase is injecting its DNA it's existing as a proas many many generations until it crosses over to the litic cycle and now all of those phase that are being released now have a combination of the phase DNA and the bacterial DNA this could have some potentially antibiotic resistant genes or other useful genes that that bacteria that is now being infected with that new phase can actually incorporate so Ways by way of a virus that genetics can kind of be scrambled and increasing that genetic diversity