Since together they complete the distance between the sugar–phosphate backbones.īut there’s one more important detail: adenine pairs with thymine, and cytosine pairs

This pattern of pairing a long and short base is called complementary base pairing, Or G, and a short base, either C or T, to fill or complete the gap to the other

The pairings of nucleotides across the DNA must include both a long base, either A But the width of a DNA molecule stays essentially constant, so Their lengths are shorter than either A or G. Here are the bases cytosine or C and thymine or T. Now I’ve added another base to the diagram, guanine or G. And DNA is a polymer made of many nucleotides. So polymers are made of many repeating units. Polymers are made of many repeating units. Human DNA is about 270 million, over a quarter billion. So how many nucleotides does it take to make a molecule of human DNA? DNA molecules vary in length, but the average number of nucleotides in a molecule of Remember, the NA in DNA stands for a nucleic acid. Repeating unit in each of the nucleic acids, DNA and RNA. Each of these building blocks is called a nucleotide, and they are the fundamental Instead, the building blocks that assemble to form the DNA are groups of one of each Individual sugars, phosphate groups, and bases. When a molecule of DNA is put together in your cells, its building blocks are not the The base is bonded to one of the deoxyribose sugars, which, in turn, is bonded to a Now I’ve added the base adenine or A to our diagram. Since the sugar–phosphate backbones parallel each other as they head their oppositeĭirections, we call this orientation antiparallel. Rooftops of the other backbone head the other way. Rooftops along one backbone point towards one end of the DNA molecule, while the If we think of the deoxyribose sugars as sugar houses with lollypop chimneys, the You can see that these sugar–phosphate backbones head in opposite directions. Length of a DNA molecule form the sugar–phosphate backbones. The chains of alternating deoxyribose sugars and phosphate groups that run along the And here’s a pattern we’ve already noted. Let’s take a closer look at DNA to examine patterns in its construction. Section, which is called: What patterns do DNA molecules form? And they also bond to their complementary base, which we’ll talk about in the next These bases bond to the deoxyribose sugars on the sugar–phosphateīackbones. Types that occur together in pairs: adenine or A, thymine or T, cytosine or C, and Connecting the sugar–phosphate backbones are nitrogenous bases of four different If you extract the DNA from just one human nucleus and lined the molecules up fromĮnd to end, they would be about two meters long. Each chain of alternating deoxyribose sugars and phosphate groups is called a The sugars run along the very long sides of a DNA molecule and are bonded between Second, DNA contains deoxyribose, a five-carbon sugar shown here in black. First, DNA is a nucleic acid, but we’ll come back to that when we talk about the The letters D-N-A stand for deoxyribonucleic acid. The orientation of the two strands that form the double helix.įirst, let’s find out what DNA is made of. Sugar–phosphate backbones, nucleotides, and complementary bases are, and describe By the time we’re finished, you’ll be able to explain why DNA is a polymer, what Patterns made by its parts, and about its shape.

In this video, we will learn about the structure of DNA such as what it’s made of,

D in dna stands for