In this video, we're going to briefly compare and contrast DNA and RNA. Recall that DNA is an abbreviation for deoxyribonucleic acid. DNA's primary function is to store genetic or hereditary information inside the cell. This is information that is passed down from one generation to the next. We'll talk more about the functions of DNA later in our course.
In this video, we're mainly going to focus on the structure of DNA. DNA forms a structure that scientists refer to as a double helix. It's called a double helix because DNA is composed of two strands, and those two strands form a helix, a twisting winding ladder-type structure that we'll discuss in detail. These two strands that make up the DNA molecule are anti parallel with respect to each other. "Anti parallel" means that the directionality of the strands goes in opposite directions.
Returning to their orientation, these two strands are connected to each other via hydrogen bonds that form between the nitrogenous base pairs. So on the left-hand side of our image over here, notice that we're showing you DNA, deoxyribonucleic acid. Once again, DNA forms a double helix structure. It consists of two strands - one strand is shown here and another there. They wind onto each other, forming hydrogen bonds between the base pairs. If we were to unwind the DNA, you would see the base pairs where c's always pair with g's, and a's always pair with t's. You can see the color coordination here.
This here represents one DNA strand, and this down here represents the other DNA strand. You can see that the blue structure represents the sugar phosphate backbone. As we know from our last lesson video, the sugar phosphate backbones of nucleic acids have directionality. Notice that this end of the sugar phosphate backbone for the strand is the 5' end, which means that the opposite end over here is the 3' end, going from 5' to 3' left to right. However, the opposite strand over here, its 5' end is on the right, which means that its 3' end is on the left.They are going in opposite directions, making these strands anti parallel to each other. If they were going in the same direction, that would make them parallel, but because they're going in opposite directions, they are anti parallel.
On the other hand, RNA is the abbreviation for ribonucleic acid. RNA has a variety of functions which we will discuss more in our course. A primary function of RNA is to act as a template for synthesizing proteins. Regarding the structure of RNA, it usually forms a single-stranded nucleotide chain rather than a double helix like DNA. On the right-hand side of our image, you can see the single strand of RNA. The single-stranded RNA also has a sugar phosphate backbone with directionality.
If this is the 3' end over here, that means the opposite end must be the 5' end. RNA uses nitrogenous bases of U instead of the T bases used in DNA, and U is specific for RNA. RNA is normally a single-stranded structure, but base pairing can still apply if it binds to itself. Sometimes RNA can fold upon itself and bind, forming complex structures. RNA can also sometimes bind to small anticodons, a topic we will delve into later in our course. You can see how RNA would base pair in the same way as DNA, replacing the T with U, which is the main takeaway. This concludes our introduction to the differences between DNA and RNA, and we'll be able to get some practice applying these concepts as we move forward in our course. I'll see you all in our next video.