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.
Sugar-Either ribose or deoxyribose (in RNA or DNA) Nitrogenous base-Adenine, guanine, cytosine, thymine (only in DNA), uracil (only in RNA) Phosphates-One to three, two of which are usually hydrolyzed to provide the energy to attach the nucleotide and form the phosphodiester bond.Source(s): biology major.ither 1 of four nitrogenous base (Cytosine, Guanine, Thymine, Adenine) Up to 3 phosphate groups. For RNA nucleotides replace deoxyribose with ribose and thymine with uracil.