Topic 2: Nucleic Acids
Nucleic acids are one of the four main macromolecules that are found in living organisms along with carbohydrates, lipids and proteins. Nucleic acids are special in that they are the molecules of inheritance, passing on information from one generation to the next. Nucleic acids form the instructions for life.
There are two main categories of nucleic acid; deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Figure 1: Comparison between the nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Nucleic acids are polymers made of monomers called nucleotides. A nucleotide consists of three parts: a pentose (5-carbon) sugar, a phosphate group, and a nitrogenous base. DNA nucleotides contain the pentose sugar deoxyribose and the bases adenine, guanine, cytosine and thymine, while RNA nucleotides contain the pentose sugar ribose and the bases adenine, guanine, cytosine and uracil. The other structural difference between DNA and RNA is that DNA is double stranded and RNA is single stranded.