We explain what nucleic acids DNA and RNA are, their molecular structure, their functions and their importance for living beings.
What are nucleic acids
Nucleic acids are macromolecules or biological polymers present in the cells of living beings, that is, long molecular chains made up of the repetition of smaller pieces known as monomers. In this case, are polymers of nucleotides linked by phosphodiester bonds.
There are two known types of nucleic acid: DNA and RNA.. Depending on their type, they can be more or less vast, more or less complex, and they can take various forms.
These macromolecules are contained in all cells (in the cell nucleus in the case of eukaryotes, or in the nucleoid in the case of prokaryotes). Even beings as simple and unknown as viruses have these stable, bulky and primordial macromolecules.
Nucleic acids They were discovered at the end of the 19th century, by Johan Friedrich Miescher (1844-1895). This Swiss doctor isolated from the nucleus of different cells an acidic substance that he initially called nuclein, but that turned out to be the first nucleic acid studied.
Thanks to this, later scientists were able to study and understand the form, structure and function of DNA and RNA, forever changing the scientific understanding of the transmission of life.
Nucleic acid types
Nucleic acids can be of two types: Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA).
Both are distinguished by:
- Its biochemical functions. While one serves as a “container” for genetic information, the other serves to materialize its instructions.
- Its chemical composition. Each comprises a different molecule of pentose sugar (deoxyribose for DNA and pentose for RNA), and a slightly different set of nitrogenous bases (adenine, guanine, cytosine, and thymine in DNA; adenine, guanine, cytosine, and uracil in DNA). RNA).
- Its structure. While DNA is a double-stranded helix (double helix), RNA is single-stranded and linear.
Function of nucleic acids
Nucleic acids, in their respective and specific way, serve for the storage, reading and transcription of genetic material contained in the cell.
Consequently, they intervene in the processes of construction (synthesis) of proteins inside the cell. The same occurs whenever it manufactures enzymes, hormones and other essential substances for the maintenance of the body.
On the other hand, nucleic acids also participate in cell replication, that is, of the generation of new cells in the body, and in the reproduction of the complete individual, since sex cells have half of the complete genome (DNA) of each parent.
DNA encodes all the genetic information of the organism through its nucleotide sequence. In that sense, we can say that DNA operates as a nucleotide template
Instead, the RNA serves as an operator from said code, copying it and taking it to the cellular ribosomes, where the proteins will be assembled. As will be seen, it is a complex process that could not occur without these essential compounds for life.
Structure of nucleic acids
Each nucleic acid molecule is made up of the repetition of a type of nucleotides, each made up of the following:
- A pentose (sugar). That is, a five-carbon monosaccharide, which can be deoxyribose or ribose.
- A nitrogenous base. Derived from certain aromatic heterocyclic compounds (purine and pyrimidine), which can be adenine (A), guanine (G), thymine (T), cytosine (C) and uracil (U).
- A phosphate group. Derived from phosphoric acid.
The structural composition of each molecule, in addition, occurs in a three-dimensional double helix (DNA) or single-stranded (RNA) form, although in the case of prokaryotic organisms it is common to find a single-stranded circular DNA.
Importance of nucleic acids
Nucleic acids are fundamental to life as we know it, since are essential for the synthesis of proteins and for the transmission of genetic information from one generation to another (inheritance). Understanding these compounds represented a huge leap forward in understanding the chemical foundations of life.
Because, DNA protection is essential for life of the individual and of the species. Toxic chemical agents (such as ionizing radiation, heavy metals or carcinogens) can cause alterations in the nucleic acid molecule, causing diseases that, in certain cases, can become transmissible to future generations.