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.
A DNA strand is simply a string of nucleotides joined together. I can show how this happens perfectly well by going back to a simpler diagram and not worrying about the structure of the bases. The phosphate group on one nucleotide links to the 3' carbon atom on the sugar of another one.In the process, a molecule of water is lost-another condensation reaction. . . . and you can continue to add more nucleotides in the same way to build up the DNA chain.xploring a DNA chain The sugars in the backbone The backbone of DNA is based on a repeated pattern of a sugar group and a phosphate group. The full name of DNA, deoxyribonucleic acid, gives you the name of the sugar present-deoxyribose. Deoxyribose is a modified form of another sugar called ribose.