Definition: A nucleic acid is a macromolecule composed of chains of monomeric nucleotides.
Monomeric nucleotides have three major parts: a five-carbon sugar, a phosphate group, and a nitrogen-containing base.
The sugar is either a ribose, forming RNA or a deoxyribose making DNA.
The nitrogen containing base can be in the form a single or double carbon ring structure.
- The single carbon ring structures, known as the pyrimidines, have three forms: cytosine and thymine, which are found in DNA, and uracil which is found only in RNA.
- The double carbon ring structures, known as the purines, have two forms: guanine, and adenine.
The four different types of DNA nucleotides are then linked together, forming a large double-stranded molecule (deoxyribonucleic acid, DNA).
Each strand’s backbone consists of joined sugars and phospate groups of the adjacent nucleotides. The nucleotides are then connected to form a double-stranded molecule that twists helically, like a spiral staircase.
The DNA molecule is the carrier of all genetic material within the cell. It has a very basic structure in which large amounts of information can be stored by a simple arrangement of nucleotides.
Artificial nucleic acids
Artificial nucleic acids include peptide nucleic acid (PNA), morpholino and locked nucleic acid (LNA), as well as glycol nucleic acid (GNA) and threose nucleic acid (TNA). Each of these is distinguished from naturally-occurring DNA or RNA by changes to the backbone of the molecule.
See also
deoxyribonucleic acid
DNA