DNA or deoxyribonucleic acid is the fundamental unit of the human genome, the basis of our being. It is the molecule that carries the genetic information, that is, the instructions that determine the characteristics of each person. Many physical features, therefore, are determined by these instructions encoded in the DNA.
An important concept when talking about DNA are the mutations that can appear in it. Mutations are alterations of the genetic material and can be of different types. Depending on where this mutation has taken place or the effect developed by it, the risk of suffering certain diseases increases.
It is important to mention that human beings share 99.9% of our DNA. What makes us different is only contained in 0.1%.
It was the Swiss biochemist Frederich Miescher who, at the end of the 19th century, managed to isolate nucleic acid molecules. Despite this, it took almost a century from that discovery until the researchers understood the structure of the DNA molecule in depth.
Where is DNA?
In eukaryotic organisms, the genetic material is found within a cellular structure known as a nucleus. Under normal conditions, the DNA is organized forming what is known as chromatin, which is only one of the lower packaging degrees of this molecule.
On the other hand, mitochondria are cellular structures that all eukaryotic organisms have. In them, there is a small amount of deoxyribonucleic acid in addition to that found in the nucleus of the cell. In the mitochondria, the energy that the cell needs to function correctly is generated.
In addition, in sexual reproduction, organisms inherit half of their nuclear DNA from the father and half from the mother. However, organisms inherit all their mitochondrial DNA from the mother. This is because only the ovules retain the mitochondria during fertilization.
How is the DNA structure?
DNA is made up of basic chemical components called nucleotides. These components in turn include:
- A phosphate group.
- A sugar group .
- A nitrogenous base.
The genetic material is organized into strands and to form them, the nucleotides are joined, through different types of bonds, forming double, complementary and antiparallel chains. The four types of nitrogenous basesmore known that form the DNA are the following:
- Adenine (A).
- Timina (T).
- Guanina (G).
- Cytosine (C).
The order of these bases in the sequence determines which biological instructions are contained in a strand of DNA. A typical example could be the following; While the ATCGTT sequence can give instructions for blue eyes, ATCGCT indicates brown eyes.
On the other hand, RNA is another type of nucleic acid. Estese is responsible for translating the genetic information of DNA into proteins . When we speak of human beings, the complete set of DNA consists of 3 billion base pairs.
They are organized into 23 pairs of chromosomes, which in turn contain between 20,000 and 30,000 genes. However, this figure is still under study as the data that has been obtained so far is not completely accurate.
How are DNA sequences used to make proteins?
The deoxyribonucleic acid instructions are used to make proteins. This fundamental process for biology is done in two steps.
First, enzymes, specialized proteins, read the information in a DNA molecule and transcribe it to the intermediate molecule called RNA.
Next, the information contained in the RNA is translated into a specific sequence of amino acids , the essential components of the proteins. There are 20 types of amino acids that can be placed forming different sequences to form different proteins.
At certain points in the cell cycle, some parts of the DNA unwind in order to be able to carry out the synthesis of proteins and other biological processes.
However, during cell division, the genetic material is in its most compact form. This presentation is called a chromosome and it is necessary to be able to transfer the genetic material to new cells. The professionals call nuclear DNA to the one that is in the nucleus of the cell. The complete set of nuclear DNA of an organism is known as its genome.