So inside every nucleus of every cell in our body we have DNA. Now, the DNA doesn't exist as a single strand. It exists as a double helix. Now, from basic biology we know that a double helix consists of these two single strands of DNA that run in an antipowerall direction opposite with respect to one another. Now, on the outside of the DNA we have the phosphate groups and we have the carbon backbone as well as the deoxyribosugars. And on the inside of that DNA double helix, we have the basis that pair with each other.