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.
Deoxyribose Sugar. Between the nitrogen-containing base and the phosphate group, which makes up the backbone of the DNA molecule, sits a sugar. It too has a ring form, composed of 5 atoms of carbon.he phosphate group is actually a triphosphate in DNA, which varies depending on which nitrogen-containing base it is binding to. The triphosphates include dATP, dGTP, dCTP, and dTTP, the second letter of the molecule name corresponding to whether it is binding to adenine, guanine, cytosine or thymine.