Endocytosis & Exocytosis

all right. So now that we've covered molecular transport of really small molecules, including passive transport and active transport, we're finally going to move on to the last section of our map of the lesson on membrane transport, which is macro molecular transport of really large molecules and of some small molecules to now, macro prefix and macro molecules really just means large. And so macro molecules include really, really large proteins Polly Sacha rides and DNA molecules as well. And these macro molecules air simply just way too large in order to diffuse through membranes or channels. And so they will not be able to use the mechanisms of molecular transport that we talked about in our previous lesson videos, including the forms of passive transport or the forms of active transport that we discussed. And so instead, these macro molecules must be transported across cell membranes, using the process of either Endo site, Asus and or Exocet Acis. As you can see down below in our map. And so we'll be able to define Endo Psychosis and Exocet assist a little bit later in our course. But for now, I'd like to foreshadow for you guys that integral membrane proteins very specific ones called fusion proteins are really important to the process of Endo Psychosis and Exocet Asus. And so these fusion proteins are integral membrane proteins that help fuse membranes, as their name implies, and both again, the process of Endo synthesis and Exocet Asus, but really moving forward in our course. We're really only going to talk about fusion proteins in the context of Exocet Asus, more specifically in the process of neurotransmitter release. But it's important to also keep in mind that fusion of membranes also takes place in Endo psychosis as well. And there are fusion proteins that we're not really going to talk about that are involved in the process of Endo Psychosis. Aziz. Well, and so, of course, because we're exploring our map using the Left most branches first, in our next video, we're going to explore Endo psychosis and the different types of Endo psychosis. So I'll see you guys in that video

in this video, we're going to introduce Endo site ASUs. And really the biggest take away of this video is that Endo site ASUs allows entry into the cell and so Endo site Oh, sis is really just defined as macro molecule engulf mint by the cell membrane, allowing entry into the cell as a lipid, vesicles. And so really the e n and Endo site Assis can remind you of the e n n engulf mint and the e n n entry to the cell. And really, there are three main types of Endo site ASUs that you guys should be somewhat familiar with and you can see that we're going to introduce those three down below. And of course, the numbers that you see up above here correspond with numbers that you see in our image down below. And so the first type of endo psychosis that you guys should know is fag Oh, site ASUs. And so if ago site assis is when large and solid materials are taken up by the process of Endo psychosis, also known as cellular eating, and again it's called cellular eating because the materials that are brought in our large and solid, and so it's almost like the cell is eating something now. The second type of endo psychosis that you guys should know is pinot site assis, and so Pena Psychosis is when small and liquid materials are taken up by the process of Endo site ASUs, also known as cellular drinking. And again, it's called drinking because the materials that are brought into the cell are small and liquid. Now, the third and final type of endo psychosis that you guys should know is really just a specific type of pinot site ASUs, which is why we have this indentation here to show that it's really just a subtype of the previous. And so this third type is called receptor mediated Endo Psychosis. And again, it's just a specific form of pinot psychosis that uses receptor proteins, and so we'll be able to see examples of each of these down below in our image. And so on the far left over here, what we have is an example of fa go psychosis and so notice over here. What we have is the cells plasma membrane, and you could see the blue background represents the outside of the South and this other background represents the inside of the self. And so you can see that during the process of faggots psychosis really large and solid materials such as an entire bacterium and multiple bacteria even can be brought into the cell here, as you can see by this era in the form of a lipid vesicles and so far ago, site Assis is a process that is utilized by some of our white blood cells and so it can be involved in immunity, essentially protecting us from harmful bacteria. But also fa go psychosis could be just a general process that's used to bring in nutrients to the cell again, another reason why it's referred to a cellular eating. Now over here in the middle, what we have is the process of Pena psychosis, and really the biggest difference is the types of molecules that are brought in because notice here, what we have are very small and liquid type of materials that are being brought into the cell. So again, it's the type of cellular drinking. Now the third and final type of Endo site, Assis, is receptor mediated endo site ASUs and notice that it's really just a specific type of Pena site Assis. You can see that the materials are very, very similar, but really, the biggest difference is that there are receptor proteins, as you can see here, we're labeling these orange structures embedded in the membrane as receptors, and these receptor proteins are, uh, involved in the Endo site topic process. And so again and all of these, the biggest take away is that it allows, and a psychosis allows entry into the cell. And so we'll be able to get a little bit of practice with these concepts and our next video. And then we'll talk about Exocet ASUs, so I'll see you guys there.

So now that we've covered Endo psychosis in this video, we're going to introduce Exocet ASUs. And really, the biggest take away of this video is that Exocet ASUs allows exiting from the cell. And so XO site Assis is really defined as vesicles fusion with the cell membrane, allowing the vesicles contents to exit the cell into the extra cellular space. And so you can think that the E X and Xa site Assis is for the e X and exit and the E X of extra cellular space. Now many biological processes rely on Exocet, ASUs, and so neural transmitters and Zim Mogens of digestive enzymes are just specific examples of substances that are released by Exocet Assis. And so, if we take a look at our image down below, notice that this here represents a cells plasma membrane, and so over here you can see the white background represents the outside of the cell or the extra cellular space. And, of course, this other background over here represents the inside of the cell. And so here. What you can see is that there's a vesicles filled with some cellular contents, perhaps neurotransmitters or perhaps Zion Mogens of digestive enzymes. And this vesicles filled with contents are, is making its way towards the cells plasma membrane. And ultimately, what it does is it begins to fuse with the cells plasma membrane until it is fully fuse with the cells, plasma membrane and the vesicles contents are released to the outside of the spell, uh, to the extra cellular space. And so you can see here that the vessel contents here are exiting the cell. And again, that's the biggest take away of this video. And so this here concludes our introduction to exercise hostess, and we'll be able to get some practice applying these concepts and our next couple of videos, so I'll see you guys there.