In this video, we're going to introduce ribosomes, and it's important to note that sometimes ribosomes are referred to as non-membranous organelles, which really just means that sometimes ribosomes are referred to as organelles that are not made of membranes, and that's what the non-membranes part refers to. Now, this is important to note because moving forward in our course, we're going to talk about a lot of different types of organelles, and most of those organelles are made of membranes. But once again, these ribosomes are not made of membranes. Now, your textbooks and professors will again sometimes refer to these ribosomes as organelles, but we need to remember that these ribosomes are non-membranous organelles. Now, ribosomes we have mentioned before in some of our previous lesson videos, but what exactly do these ribosomes do for the cell? And so these ribosomes are really just molecular machines that build proteins in all living cells and so ribosomes are found once again in all living cells regardless if those cells are plant cells or animal cells or eukaryotic cells or prokaryotic cells it does not matter. Again, ribosomes are found in all living cells, and they are really molecular machines that build proteins. Now the process that's conducted by these ribosomes that builds these proteins has a specific name that is called translation. And so translation we can define as the process that is conducted by ribosomes that allows them to build proteins. And later in our course, we're going to talk a lot more details about this process of translation, but for now in this video, all you should know is that ribosomes will build proteins by performing a process called translation. Now these ribosomes when they are inside a cell, they can either be free ribosomes that are free-floating in the cytoplasm or they can be attached ribosomes, and these attached ribosomes are not free-floating instead these attached ribosomes are going to be attached to another organelle, for example, the rough endoplasmic reticulum, that we'll get to talk more about this rough endoplasmic reticulum later in our course. But for now, if we take a look at our image down below, we can get a better understanding of these free and attached ribosomes and so notice right in the middle what we're showing you is our representation of our Eukaryotic cell and, notice that we have these blue circles throughout our Eukaryotic cell and they're all over the place, and so you can find all of these blue circles in your Eukaryotic cells. Now these blue circles, if we were to zoom into one of these blue circles, that's what this image over here is showing, you would notice that these blue circles are indeed ribosomes. And again these ribosomes are going to be performing translation and building proteins. Now, all of these blue circles that you see that are free-floating in the cytoplasm are going to be free ribosomes. And recall that the cytoplasm is really just going to be the area that is inside of a cell but outside of the organelle. So all of these, blue circles that you see, in these little areas here, those would be free ribosomes. And so these are going to be floating in the cytoplasm of the cell. So we can fill that in here. And again, these ribosomes are going to be performing translation, and so the ribosome in this image is represented by this blue structure that you see over here. And notice that this ribosome is building a chain of protein, here so we can say that this is our growing protein that is being built by the ribosome. Now again, some of the ribosomes will be free ribosomes, free-floating in the cytoplasm, but other ribosomes that you can see in these positions are attached ribosomes that are attached to another organelle. And so if we zoom into this area right here what you'll notice is that we can see some attached organelles, some attached ribosomes to, the rough endoplasmic reticulum. And so notice that the rough endoplasmic reticulum in this image is, being indicated by this, reddish structure that you see right here. And what you'll notice is that this rough endoplasmic reticulum, has these attached ribosomes. So, these attached ribosomes are attached to the rough endoplasmic reticulum. And again, we'll get to talk more about the rough ER or the rough endoplasmic reticulum more as we move forward in our course. But for now, notice that within these, eukaryotic cells you'll find some ribosomes that are free ribosomes, free-floating in the cytoplasm, and you'll find some ribosomes that are attached ribosomes that are attached to other organelles such as the rough ER for example. And so this here concludes our brief introduction to ribosomes, and we'll be able to learn more as we move forward in our course, so I'll see you all in our next video.