Beaded Necklace is one of my many names for nucleic acids. the reason being that they are made up of tiny sub-units called NUCLEOTIDES. to complicate things further, nucleotides themselves have three parts: NITROGENOUS BASES, SUGAR and PHOSPHATE. we shall cover them in more detail later on!
Nucleotides fuse together to form “Polynucleotide Chains” (poly: many), another name for nucleic acids. These chains have “Directionality“, or simply put, the two ends of these chains are different from each other. The ends are numbered as 3′ and 5′. The 3′ end has Hydroxyl group (-OH) of the sugar and 5′ end has the sticking out.
As new nucleotides attach, the OH of chain attaches to the phosphate of incoming nucleotide, hence the chain grows at its 3′ end. The bonds formed are called Phosphodiester Linkage.
An ester bond is typically characterized by a carbon bound to three other atoms: a single bond to a carbon, a double bond to an oxygen, and a single bond to an oxygen. Since a phosphorus is present instead of carbon, and the phosphorus has single bonds to 2 oxygens, the name “Phospho-di-ester” (di: two) is used.
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