Introduction to Membrane Transport

Jason Amores Sumpter
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in this video, we're going to begin our introduction to membrane transport, and so biological membranes are semi permeable. And what this means is that they can act as barriers to essentially prevent diffusion of molecules now semi permeable or, in other words, selectively permeable. Our terms that are synonyms, toe one another selectively permissible and semi permeable are synonyms and really what this means selectively, permeable or semi permeable. It just means that biological membranes they're really, really picky about what they allowed to cross the membrane and so permeable is really a word that just refers to how penetrate herbal something is and selectively just means that it's picky. It's going to select what is allowed to cross and what isn't allowed to cross on semi is basically a word that means partial and so semi permeable means partially penetrate herbal again, just meaning that it's really, really picky about what it allows to cross the membrane. So let's take a look at our example image down below at the selectively permeable biological membranes. So notice here in the middle what we have is our biological membrane, which is a semi permeable biological membrane, and notice that some molecules like this yellow molecule here are able to get through the membrane really, really easily. But not all molecules can get through the membrane. Some molecules are not able to cross, and so notice these molecules air like stupid barrier. They cannot get through, and the membrane is again acting as a barrier asked saying. Excuse me, do you read? Guys over here have an appointment to get across the membrane. And so essentially, this whole cartoon right here is just supposed to represent that membranes act as biological barriers to prevent the diffusion of some molecules. And so these red molecules are not able to diffuse across from an area of high concentration to an area of low concentration. But other molecules like this yellow one over here who's laughing at the red ones that can't get through, uh, they can get through the membrane. And so that's, um, something important to keep in mind. And so, in terms of what molecules are allowed to cross the membrane and what molecules are not allowed to cross the membrane, we'll get to talk about that in our next lesson video. So I'll see you all there