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.
Combinations of these atoms form the sugar-phosphate backbone of the DNA -- the sides of the ladder, in other words. Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder.(It takes two bases to form a rung -- one for each side of the ladder.). A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide.Nucleotides are abundant in the cell's nucleus.ombinations of these atoms form the sugar-phosphate backbone of the DNA -- the sides of the ladder, in other words. Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder.