BIOCHEMISTRY - Key Regulators and Biological Fluids of the Human Body - 2016

3. NUCLEIC ACIDS

3.1. General Characteristics

Nucleic Acids were first discovered in the Cell Nucleus (from the Latin nucleus meaning kernel or core) by F. Miescher in 1869, which is how they got their name.

Nucleic acids play a fundamental role in the storage, transmission, and expression of Genetic information.

There are two main Types of Nucleic acids:

- Deoxyribonucleic Acids (DNA), responsible for storing and transmitting hereditary information;

- Ribonucleic Acids (RNA), responsible for METABOLISM/35.html">Protein Biosynthesis.

Cellular properties are determined primarily by Proteins, the structural blueprints of which are "encoded" in DNA molecules—the major components of Chromosomes. This structural information is transcribed into RNA molecules, which then direct Protein Synthesis.

General characteristics of nucleic acids:

1) they are high-molecular-weight linear heteropolymers with molecular weights ranging from 250 to 1.2 • 10⁵ kDa;

2) their monomeric units are NUCLEOTIDES (Fig. 10), which consist of:

- nitrogenous bases (adenine, guanine, thymine, cytosine, uracil);

- a pentose residue (ribose or deoxyribose);

- a phosphoric acid residue;

Class="center">Fig. 10. A nucleotide—the monomer of a nucleic acid polymer

3) DNA is localized in The Nucleus, Mitochondria, and Plastids, whereas RNA is found in the Cytoplasm, Ribosomes, and temporarily in the nucleus, as well as in Mitochondria and Plastids (from the completion of its synthesis until export from the organelle).