Types of Membrane Proteins - Video Tutorials & Practice Problems

Types of Membrane Proteins

So now that we know that proteins play a major role in forming biological membranes in this video, we're going to introduce the different types of membrane proteins. Now, really, there are two main types of membrane associated proteins, and we have those two listed down below now. The first are the integral membrane associated proteins, and the second type are the peripheral membrane associated proteins. Now the integral membrane associated proteins, as their name implies, are non conveniently integrated into the phosphor, a lipid bi layer as we can see down below. And usually these integral membrane proteins spanned the entire lipid bi layer so that they have an extra cellular portion and an interest cellular portion. And so, of course, this purple protein that we see down below is our integral membrane protein. And again we could tell, because it's completely integrated and spanning our fossil lipid bi layer. Now the next type, the peripheral membrane associated proteins as their name implies, these air on the periphery or the perimeter of the lipid bi layer. And they do not span the entire lipid bi layer like integral membrane proteins dio and so notice down below. In our image this blue protein right here is on the periphery or on the perimeter of the lipid bi layer. And so this is going to be our peripheral membrane associated protein. Now there is a subcategory of peripheral membrane associated proteins, and those are the lipid linked membrane associated proteins. And so again, the lipid linked membrane associated proteins our peripheral membrane associated protein. So they're going to be found on the periphery. But really, what makes these lipid linked ones so distinct is that these air peripheral membrane proteins that air co violently anchored toe lipid groups within the violator. And, of course, if you have a protein that is co Vaillant Lee linked to a lipid group that's going to make it a lipoprotein. And so these lipid linked membrane associated proteins are peripheral lipo proteins. And so if we take a look at our image down below right here, notice we're showing you a lipid linked membrane associated protein here and notice that it is indeed on the periphery, and the protein is not really spanning. The membrane like are integral membrane protein waas. Instead, it is on the periphery, so that makes it a peripheral membrane protein but also noticed that it's co violently attached to this lipid group that we see right here. And that is really what distinguishes it as its own, subcategory within the peripheral membrane proteins. Now, as we move forward in our course, we're going to talk even more details about each of these different types of membrane associated proteins. But for now, this here concludes our introduction to the types of membrane proteins, and I'll see you guys in our next video.

Which of the following are covalently attached to lipid molecules in the cell membrane? 

a) Integral proteins.

b) All membrane proteins.

c) Peripheral proteins.      

d) Lipid-anchored proteins.

• A. Integral proteins
• B. All membrane proteins
• C. Peripheral proteins
• D. Lipid-anchored proteins

Membrane Protein Functions

So in our last lesson video, we introduce the different types of membrane associated proteins. But what in the world do these membrane associated proteins even do for a cell? Well, in this video, we're going to talk about some membrane protein functions. And so it's important to note that membrane associated proteins can actually perform a wide variety of functions. So many different functions that it's not possible toe list All of the membrane associated protein functions on this page, but what you'll notice is down below in this table, we're showing you guys some of the more common functions that membrane proteins can have. And so the first function here that we're showing you guys is recognition. And so some membrane associated proteins can be used purely for recognition and can mark the cell for identification. And so, just like your ID can identify you. Some membrane associated proteins can be used to identify the cell, and that allows our immune cells to distinguish healthy cells from foreign invading cells. Now, other membrane associated proteins can be used in Anchorage, and this allows a sell and a cell site of skeleton to be anchored to the E. C. M or the extra cellular matrix. Now, other membrane associated proteins can be used in trans duck shin specifically signal transaction so they can act as signal molecule receptors and transducer, a signal from the outside of the cell to the inside of the cell or vice versa. Transducer a signal from the inside of the cell to the outside of the cell, allowing for communication to occur. And so here we have an image of a signal receptor to remind you of that function. Now, other membrane associated proteins can act in transport and allow for molecular transport across the membrane, either from the outside of the cell to the inside of the cell or vice versa from the inside to the outside. And so, just like a car can be used to transport cargo membrane. Associated proteins can also be used to transport molecular cargo. Now, other membrane associated proteins function in linkage and basically can connect to cells via a protein linkage. And so, just like two paper clips can be linked together In this fashion, protein linkages again can link together two different cells, and then last but not least, other membrane associated proteins can function as enzymes. And, of course, we know that enzymes will catalyze and speed up the rate of chemical reactions. And so, of course, there are many, many different types of enzymatic processes, and these membrane associated proteins can act as many different types of enzymes to catalyze all of these different types of enzymatic processes. And so here we're showing you an image of an enzymatic process to remind you of that function. And so what you'll notice here is that the first letter of all of these general functions here actually spell out the word rattle. And so over here we have a rattle toe. Help remind you of these generalized functions. Now, as we move forward in our course, we'll be able to see some examples of how membrane associated proteins can function in these different ways. But for now, this is our general introduction to membrane protein functions, and I'll see you guys in our next video