The components of DNA and how they interact to form a double helix structure

(Answer supplemented with whiteboard annotations)

The structure of DNA consists of three pivotal structures. A deoxyribose pentose sugar made up of five carbons. An ionised phosphate group and a nitrogenous base. Whilst the sugar and the phosphate are the same in DNA, the nitrogenous base varies. The base can be 1 of 4 structures. (Adenine, Guanine, Thymine or Cytosine) Many of these DNA structures come together to form a DNA double strand. For this to happen, two processes happen. Firstly, the DNA structures form a (sugar phosphate backbone) and secondly, (complementary base pairing) takes place between two DNA strands.

And there you have it! The 3 constituents of DNA (Phosphate group, Deoxyribose Pentose sugar and one of four nitrogenous bases) On posters, you wont usually see the DNA looking like this, instead you will see a coiled structure. This is because the DNA wants to coil as much as possible to keep a tonne of genetic material in such a tiny space. In fact, if you were to line all the DNA in every cell of a human body, it would stretch from the earth to the sun 100 times!