In this video, we're going to introduce mitochondria structure, and so mitochondria are usually shown with this bean-shaped structure, as you see right here. You'll find that, looking across your textbook, the mitochondria are almost always shown with this bean-shaped structure. However, it's important to note that mitochondria can actually vary in their shape and they don't always have this same exact bean-shaped structure. The mitochondria can take on a variety of different structures that are elongated and flattened, among other forms. Now, it's also important to note that mitochondria actually have their own ribosomes. They have their own mitochondrial ribosomes, and the mitochondrial ribosomes are different than the ribosomes from the rest of the eukaryotic cell. Also, mitochondria have their own DNA. They have their own mitochondrial DNA that is independent of the nuclear DNA or the DNA that is found in the nucleus. And so, the DNA in the mitochondria will be different than the DNA that is found in the nucleus.

Now, mitochondria actually have two membranes, and those two membranes are an outer membrane and a folded inner membrane. And so, the inner membrane is going to have lots and lots of folds, and those folds in the inner mitochondrial membrane are referred to as cristae, and so you should be familiar with this term 'cristae'. Now, in between the two mitochondrial membranes, in between the outer mitochondrial membrane and the folded inner mitochondrial membrane, is a region that is called the intermembrane space. And so the intermembrane space is defined as the region in between the two mitochondrial membranes. Now, there's also a space in the mitochondria called the matrix or the mitochondrial matrix. And again, this is a space or a region within the mitochondria, specifically it's a region within the inner membrane of the mitochondria. And so, it is going to contain enzymes, ribosomes, and mitochondrial DNA.

If we take a look at our image down below, we can get a better understanding of the structure of the mitochondria. Once again, the most important thing to note is that the mitochondria are going to have two membranes. It has an outer membrane, which we can highlight here in red, going all the way around the perimeter. But then it also has a folded inner membrane, and the folded inner membrane, you can see, is going to be extremely highly folded here, and it goes all the way around, as you see right here. Now, the inner membrane, again, is going to be very folded, and those folds in the inner membrane are specifically referred to as cristae, and so you should be familiar with that. Now again, there is a region in between the inner and outer membrane called the intermembrane space. So, the intermembrane space, if we were to highlight it, would go all the way around and is going to be, again, in between the inner and outer membranes, as you see here highlighted in that dark pink. And then there's another region called the mitochondrial matrix; this is going to be the region inside of the inner mitochondrial membrane and so the matrix would be this region highlighted here in green. And so, this is really important to keep in mind, to differentiate the intermembrane space from the mitochondrial matrix.

Now, in the mitochondrial matrix, if we were to zoom into this particular region, right here, of the mitochondrial matrix, that's what this box is, this is where you're going to find the mitochondrial enzymes, mitochondrial ribosomes, and mitochondrial DNA. And so, notice in this image, the mitochondrial ribosomes are being shown in green here. Notice that the mitochondrial enzymes are being shown in this grayish circle, right here. And then notice that the mitochondrial DNA is circular in its shape and it is also going to be found in the mitochondrial matrix.

This here concludes our brief lesson on mitochondria structure and this will be very important to keep in mind as we move forward in our course. And so, I'll see you all in our next video.