 Okay, so let's use cell membrane to build some organelles. First of all, I don't want you to forget that we actually, the nucleus itself is surrounded in cell membrane. So I have a visual here that this is my nucleus. So this is cytoplasm here. We can't see the real cell membrane. We can see that my nucleus is made of cell membrane and it has these pores inside of it so information can get in and out. Now, the first structure that I want to look at is called the rough endoplasmic reticulum. The rough endoplasmic reticulum is like this crazy maze labyrinth of cell membrane that is, think of it as literally hollow inside, just like a labyrinth would be. You know, you can walk inside a labyrinth. You could walk inside the rough endoplasmic reticulum. I'll write that down for you in just a second here. It's connected to the nucleus of the cell. So the cell membrane that makes up the nuclear envelope almost like continues out and folds around and becomes the rough endoplasmic reticulum. So let's start, oh dear, let's start by looking at, by writing this down, I can do this, really I can. Rough endoplasmic reticulum. And a.k.a. rough E.R. Now, can you say rough E.R. on a test instead of rough endoplasmic reticulum? Yeah, I probably would accept it, but you better know that E.R. stands for endoplasmic reticulum in case I use endoplasmic reticulum. And it's rough. Rough with ribosomes, what? The rough endoplasmic reticulum is a maze of cell membrane with ribosomes like embedded in it, like a jeweled outfit with a whole bunch of jewels all embedded in it and the jewels are the ribosomes. Who remembers? What does a ribosome do? Go ahead, shout it out, shout it out loud. You will learn to watch these lectures somewhere where it's okay for you to shout out loud. Ribosomes make, or I like the word build better, they build protein. That gives you a hint as to the function of my friend, the rough E.R., the R.R. The rough endoplasmic reticulum is responsible for, how should we say this, like modifying or processing? What? Proteins. We're going to talk about proteins, we're going to talk about protein structure and how proteins are actually strings of amino acids that fold into all sorts of awesome shapes and the folding happens in the rough endoplasmic reticulum. There's also another kind of endoplasmic reticulum, so let's look at that one as well.