The sympathetic nervous systemâs fight-or-flight response is your built-in mechanism for safely escaping a life-threatening emergency, such as a lion lurking behind a bush.
The basic building block of DNA is called a NUCLEOTIDE. A nucleotide is made up of one sugar molecule, one phosphate molecule and one of the four bases. Here is the structural formula for the four nucleotides of DNA. Note that the purine bases (adenine and guanine) have a double ring structure while the pyrimidine bases (thymine and cytosine) have only a single ring.
For example, in adenosine monophosphate (AMP), the phosphate is connected to the sugar via an oxygen-carbon bond (the oxygen comes from the phosphate group, the carbon from the sugar) and the sugar is in turn connected to the nitrogenous base (adenine) via a carbon-nitrogen bond, the carbon being on the sugar (different from the one above) and the nitrogen being on the base (adenine)