- What are nucleic acids
- Nucleic acid types
- Function of nucleic acids
- Structure of nucleic acids
- Importance of nucleic acids
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 polymers biological substances present in cells of the living beings, that is, long molecular chains made up of repeating smaller pieces (monomers). In this case, they are nucleotide polymers 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 infectious agents as simple as virus These macromolecules are stable, bulky and primordial.
Nucleic acids were discovered in the late 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 the life.
Nucleic acid types
Nucleic acids can be of two types: Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA). They differ by:
- Its biochemical functions. While one serves as a "container" of the Genetic information, the other serves to transcribe your instructions.
- Its chemical composition. Each comprises a molecule of pentose sugar (deoxyribose for DNA and ribose for RNA), and a slightly different set of nitrogenous bases (adenine, guanine, cytosine, and thymine in DNA; adenine, guanine, cytosine, and uracil in 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 the genetic material contained in the cell.
Consequently, they intervene in the processes of construction (synthesis) of protein inside the cell. This process occurs whenever the cell manufactures enzymes, hormones and other peptides essential for the maintenance of the body.
On the other hand, nucleic acids also participate in cell replication, that is, the generation of new cells in the body, and in the reproduction of the complete individual, since sex cells possess 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, RNA serves as an operator based on said code, because it copies (transcribes) it and takes it to the cellular ribosomes, where the proteins are assembled. 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:
- A pentose (sugar). It is a five-carbon monosaccharide, which can be deoxyribose or ribose.
- A nitrogenous base. It is derived from certain aromatic heterocyclic compounds (purine and pyrimidine). It can be adenine (A), guanine (G), thymine (T), cytosine (C), and uracil (U).
- A phosphate group. It is derived from phosphoric acid.
The structural composition of each molecule, in addition, is given in a double-stranded (DNA) or single-stranded (RNA) helical form, although in the case of prokaryotic organisms, it is common to find circular DNA molecules called plasmids.
Importance of nucleic acids
Nucleic acids are essential for life as we know it, since they 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.
Therefore, the protection of DNA is essential for the life of the individual and of the species. Toxic chemical agents (such as ionizing radiation, metals heavy substances or carcinogenic substances) can cause alterations in nucleic acids, and cause diseases that, in certain cases, can be transmitted to future generations.