The Functions of DNA and RNA Are vital for the body. They are essential acids for human survival and complement each other.
The main function of DNA or Deoxyribonucleic Acid is to contain the genetic information of a living being, said genetic information is nothing more and nothing less than the"recipe"of all physical and structural characteristics of the organism.
In DNA is contained information on how many cells each organ should have, how often they should be regenerated, how they should work to maintain a balance within the organ and with other body systems.
This information is contained in the form of 2 strings coiled and joined together by nucleotides, which form what looks like the steps of a ladder.
RNA or Ribonucleic Acid is considered a secondary of DNA with a less important function, when in reality without it, DNA would be a great pile of information that would not serve anything, because it is confined to the nucleus of Eukaryotic cells , From where he can not leave for any reason.
The functions of these molecules are vital for the survival of each living being and are summarized below.
Main functions of DNA and RNA
DNA Functions
1- Replication
DNA is present in each and every nucleus of the body cells, no matter what organ or tissue they form, the information must be complete, although not all is necessary for that area of the body.
Therefore, the DNA must be replicated every time a cell is to be divided, since the two daughter cells that remain after this division (known as mitosis) must have exactly the same information as the progenitor cell.
However, it is known that there are cells of the body that reproduce faster than others, such as the epidermis (outermost layer of the skin), which is completely renewed every 28 days.
To carry out this renewal, cells must replicate quickly, but how can they replicate so quickly if each cell has at least 2 meters of DNA strings?
The answer is simple even if the process itself is not, because in order for the 2 daughter cells to be left with the same genetic material, the 2 meters of DNA string must be replicated with the least amount of errors possible. For this, a large number of enzymes and processes that allow the following simultaneous activities enter into the process:
- The chain unwinds (from being a helix, to being a linear structure)
- The chains are separated exactly by the middle
- Form the missing part of each chain
Only if this occurs at the same time can it be achieved that meters and meters of DNA from many cells being replicated will be duplicated to renew tissues.
2- Encoding
All the functions of the cells are carried out by proteins. Each order that the nucleus emits is actually a key message different from the previous one in the order in which the proteins are presented.
Thanks to this, one of the main functions of DNA is to synthesize or"make"the proteins that each cell needs, since a liver cell does not have the same functions as the kidney, so its"instructions"are not the same , Ie their proteins are different.
The work of DNA itself is to know which proteins are used for each function of the cell, give the order to synthesize it and send the recipe so that the Rough Endoplasmic Reticulum (RER) can do them.
3- Cell differentiation
Have you ever wondered how an entirely different new being can form from an egg and a sperm? The answer is DNA.
At the beginning of the formation of a new being there is only one cell, a product of the union of the ovum and the sperm, with the genetic characteristics of the mother and the father.
This cell is known as stem cell , From which all the others are derived, by means of a process called differentiation, carried out thanks to the information contained by the DNA.
DNA knows how many cells there must be and what functions they must fulfill to form each organ and every part of the body, such as the lungs, liver, stomach, to name a few.
To differentiate the structure of a cell from one organ to that of another, DNA simply governs the structural characteristics it must have through the proteins that it allows it to synthesize during its formation.
It also assigns its function through the protein recipes that allow you to use, which will always be exactly the ones you need according to the organ you are in and your place within it.
For example, protein recipes that stomach cells can use will mainly be the creation of enzymes and stomach acids, while those in the brain will mainly be substances that allow the transmission of nerve impulses.
In this way, all cells have the complete information in their core, but only have access to the one that allows them to carry out the function for which they were created.
4- Evolution and adaptation
Evolution is the process by which living beings change their physical and genetic characteristics to adapt to the environment and survive.
Adaptation is the set of physical changes that a living being experiences in order to survive the environment, especially when it is adverse.
For either of the above two mechanisms DNA is necessary, since for a physical change in a species, it is necessary to do it at the genetic level. Only then will the change continue in their offspring and will not disappear. AND This change at the genetic level is also known as mutation.
Mutation is a variation on the genetic code, this variation can be either random or by adaptation, as mentioned in the most famous example of Lamarck .
Giraffes were animals with a neck no longer than that of a horse, but as time went by and food shortened to heights they were able to obtain it, they struggled and stretched more to reach it.
With the passage of time, this modification caused the species to lengthen its neck, so at the end of all generations, remained exactly as it is known today. However, the giraffe specimens that did not achieve this adaptation to the environment perished.
For the giraffes to start having a longer neck, there had to be a modification in the DNA, so the characteristic passed from generation to generation without getting lost.
RNA Functions
RNA is the only contact with the outside of the nucleus that has the DNA. To carry out its functions, it is divided into 3 types, each with a different function and characteristics.
1- Messenger RNA (mRNA)
It is responsible for carrying the orders of the DNA to the cytoplasm, that is to say, the organelles that are the indicated ones to carry them out. It does this by means of a sequence of proteins dictated by the DNA, that only the organelle for which they are destined can understand.
2-ribosomal RNA (rRNA)
It is responsible for providing the exact recipes or sequences for each cellular function. That is, if the order of the DNA is that 5 proteins are created for the muscle, the rRNA will be in charge of providing the exact sequence for those proteins, since the organelles, although they are able to follow orders, do not know the sequences.
3-Transfer RNA (tRNA)
A protein is actually a chain of amino acids, which are in themselves like the beads of a necklace, each of a different color. Depending on how the colors are ordered is the protein to be formed.
Once DNA gave the order to create a protein, the mRNA was taken to the corresponding organelle and the rRNA provided the recipe. The tRNA is responsible for giving the ingredients, ie the amino acids, so that they can be sequenced correctly and create the new protein.
As can be seen, DNA and RNA are a fundamental part of an organism's life, and neither can survive without the other, for they are in themselves two complementary parts of a structure.
References
- Molecular Biology of the Cell. 4th edition. Alberts B, Johnson A, Lewis J, et al. New York: Garland Science; 2002. Retrieved from ncbi.nlm.nih.gov.
- Lee TI, Young RA. Transcription of eukaryotic protein-coding genes. Annual review of genetics. 2000; Pages 77-137. Retrieved from: cm.jefferson.edu.
- Compare and Contrast DNA and RNA By Samuel Markings, retrieved from sciencing.com.
- DNA - RNA - Protein Josefin Lysell, Medical Student, Karolinska Institutet Fredrik Eidhagen, Medical Student, Karolinska Institutet, Sweden. Retrieved from nobelprize.org.
- DNA: Definition, Structure & Discovery by Rachael Rettner, Senior Writer | June 6, 2013. Retrieved from livescience.com.
- The Structures of DNA and RNA by Watson, p. 2 - 25. Extract of PDF document retrieved from biology.kenyon.edu.
- G-quadruplexes and their regulatory roles in biology by Daniela Rhodes Hans J. Lipps Nucleic Acids Res (2015) Published: 10 October 2015. Retrieved from academic.oup.com.