Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are made up of nucleic acids found in the nuclei of living cells. They are the vehicles of genetic inheritance.Nucleic acids are condensation polymers of nucleotides.
The building blocks
Three types of chemicals make up the building blocks for nucleic acids.
These are based on the inorganic acid H3PO4 (phosphoric acid). Phosphoric acid
Condensation of phosphoric acid
Two important reactions of the hydroxyl groups:
• with alcohols to form ester groups
• with amines to form amide groups
The sugars in DNA and RNA are pentose.
• DNA deoxyribose
• RNA ribose
Both these sugars have hydroxyl groups. These groups react with carboxylic acids and phosphoric…show more content… In all nucleotide molecules the bonds holding the phosphate group to the sugar and the base to the sugar are both products of condensation reactions. Water is eliminated when they form. In both cases the oxygen to form the water has come from the sugar's -OH groups. Formation of a nucleotide
Nucleotides can link together by the formation of phosphate ester bonds. The hydroxyl group of a phosphate on one nucleotide undergoes a condensation reaction with the hydroxyl group on the carbohydrate ring of another nucleotide. The process may continue, building up nucleic acid molecules. These are polymers called polynucleotides. Formation of a polynucleotide
Nucleic acids are the 'building blocks' of DNA and RNA.
The structure of DNA
DNA is formed from two polynucleotide chains. Each chain has a helical structure (a helix), in other words the molecule is coiled like a spring.
The two helices are then intertwined to give a double helix. The bases are on the inside of the helix and the phosphate groups are on the outside.
The two helices are held together by pairing of the nucleotides' bases through hydrogen bonding. Because the double ring purines are bigger than the single ring pyrimidines the structure can only form with purines