In this video, we're going to introduce the classes of membrane transport proteins. Now really there are 3 types of transport proteins that are classified according to how they operate or how they work. And so the very first type of transport protein that you all should know are the uniporters, and uni is a prefix that means 1 or singular. And so uniporters are going to transport just one molecule at a time in just one direction across the membrane. If we take a look at the image down below at the uniporter, notice that this protein that's in the membrane right here is going to be the uniporter, and uniporter proteins are going to transport just one molecule across the membrane in one direction.
So we have one molecule here in one direction across the membrane. This protein would be a uniporter. Now, the second type of transport protein that you all should know are the symporters. The symporters are going to co-transport at least 2 molecules, at a time in the same direction across the membrane. You could think the "s" in symporter is for the "s" in same direction across the membrane.
When we take a look at the image down below at the symporter here, which would be this protein here, notice that the symporter is going to transport at least 2 molecules across the membrane, and so notice that we have this red molecule right here and we have the green molecule right here, and notice that both the red and the green molecule are being transported symporter, because they're being transported in the same direction across the membrane. Now, last but not least, the third type of transport protein you all should know are the antiporters. Anti is a prefix that basically means the opposite. And so antiporters are going to be, co-transporting at least 2 molecules at a time just like the symporters do, but instead of transporting them in the same direction across the membrane, antiporters are going to be transporting the 2 molecules in opposite directions across the membrane. Let's take a look over here at the image on the far right hand side at the antiporter, which would be this membrane protein right here.
Notice it's also transporting 2 molecules. It's transporting the red molecule in this direction and the green molecule in this direction. And because the 2 molecules are being transported in opposite directions, that's what makes this an antiporter, and so we can write opposite directions right here. This here concludes the lesson on the different classes of membrane transport proteins and we'll be able to see examples of all of these types as we move forward throughout our course. This here concludes our lesson and I'll see you all in our next video.