hey everyone it's sarah with registerednessrn.com and in this video i'm going to go over the life cycle of hiv so let's get started here i have a basic hiv virus and beside of it is a helper t cell now the hiv virus is a retrovirus it cannot grow or multiply without a host cell and the hiv virus loves cells that have a cd4 receptor on its surface because the way it's designed it can easily access that receptor and once it access and attaches to that receptor it gets inside the cell then inside the nucleus where it takes over the cell's function and it causes that cell to produce more hiv so once it's done producing the amount of hiv it wants to produce it kills that cell and then all that fresh new hiv goes and just repeats this cycle so in order to do this it has to be designed in a certain way so let's look at the anatomy of the virus the virus is surrounded by proteins glycoproteins and here you will see those glycoproteins and the particular part i want you to pay attention to are these little knobs here these little protein projections this is known as gp120 glycoprotein 120 because this protein is essential in helping attach to this cd4 receptor once we've done that the hiv virus can attack and enter the cell then on the inside of the cell i like to think of it as its little suitcase because hiv knows it's not going to stay like this it's whole goal is to get in and fuse with this cell so it just needs to bring along the basic supplies and i want you to remember some things that it's going to bring along three enzymes these enzymes are very important in the life cycle of hiv first enzyme is called reverse transcriptase second is integrase and then the third one is protease also inside is a single strand of rna so now let's look at the life cycle of hiv and how it actually gets inside this cell it integrates itself it starts replication assembly budding and then we get new mature hiv so the first step is attachment what happens is that these glycoproteins specifically gp120 goes and attaches itself to the cd4 receptor on that cell surface here we have a helper t whenever that happens there's also binding of a co-receptor this could either be ccr5 or cxcr4 whenever that happens hiv has gained entry into the cell now what it's going to do the next step is fusion it's going to fuse itself with this helper t cell and whenever it does that it's going to take its hints suitcase as i called it earlier it's contents and just dump it inside the cell because the whole goal of what it's got to do is it's got to set up shop and take over that cell so it has some things to do once this material is dumped in we have our enzymes and we have our rna it knows that this rna needs to turn into dna so it brought along an enzyme we're going to have reverse transcription that's the next step so reverse transcriptase is going to turn that rna into double-stranded dna this viral dna now needs to integrate itself inside the cell's nucleus so it moves to the nucleus it gets inside and now it releases another enzyme that it brought along called integrase so here it sees the cell's dna so integrase allows the viral dna that was created to integrate inside the cell's dna so now it's just taken over the cell and it can control the cell's function so now the next step is to replicate so we have replication we have the creation of these long protein chains rna they start to become assembled our next step and move up because it needs to get out of this cell so it moves up towards the cell surface it starts to grow outward and it's budding that's our next step and once budding is complete it pops off and whenever it pops off we have maturity and the new hiv material in there releases another enzyme called protease and what that does is it takes those long chains of proteins and cuts them makes them shorter and then that helps with maturity of the hiv virus once this process has been completed to the hiv satisfaction it will kill this cell and then new hiv is going to go around by new cells to infect and the cycle happens over and over now why do you want to be familiar with the life cycle of hiv well in order to understand how anti-retroviral therapy works for a patient who has hiv you have to really have a basic understanding of this whole life cycle because these medications a patient takes a combination of them will target certain parts of this life cycle like the attachment step or the fusion step or the assembly step and by targeting that we're going to limit how much hiv can be created hence in the blood so whenever a patient starts taking art they want to do it as soon as possible the earlier we can start the better okay so that wraps up this video over the life cycle of hiv and if you'd like a more in-depth lecture over hiv and aids don't forget to access the free video in the youtube description below