DNA (Deoxyribonucleic acid) is a molecule present in the nucleus of cells of all living beings and that carries all the genetic information of an organism .
It is formed by a spiral-shaped double strand (double helix), composed of nucleotides.
DNA structure
The DNA molecule is made up of three chemicals:
- Nitrogenous Bases– Adenine (A), Thymine (T), Cytosine (C) and Guanine (G);
- Pentose– A sugar that has molecules formed by five carbon atoms;
- Phosphate– a phosphoric acid radical.
DNA molecule structure
The two strands that make up DNA wind around each other and join together through hydrogen bonds , which form between the 4 nitrogenous bases of the nucleotides:
- A – Adenine;
- T – Thymine;
- C – Cytosine;
- G – Guanine.
Hydrogen bonds are formed between base pairs: AT and CG . Adenine with Thymine and Cytosine with Guanine.
DNA is so tightly packed in the cell nucleus that if you could stretch it out, it would be 2 meters long.
All forms of life on the planet, with the exception of some viruses, have their genetic information encoded in the sequence of the nitrogenous bases of DNA.
See also: What are Nucleic Acids?
Gene
Genes are units of hereditary information that make up chromosomes , formed by special sequences of hundreds or thousands of pairs of nitrogenous bases (AT or CG) .
They determine both the characteristics of the human species and the characteristics of each individual.
Genes specify the amino acid sequences that serve as the basis for cellular protein synthesis .
These proteins, usually enzymes, act on the structure and metabolic functions of cells and, consequently, on the functioning of the entire organism.
chromosomes
The different DNA sequences make up the chromosomes . Human beings have 46 chromosomes: 23 received from the mother and 23 from the father. Each pair of chromosomes is made up of numerous genes.
genome
The Genome is all the hereditary information encoded in an organism’s DNA or RNA , in the case of viruses. It is the set of all genes of a given species.
DNA or genome sequencing is the technique used to determine in which order the nitrogenous bases (Adenine, Thymine, Cytosine, Guanine) are found in DNA.
Sequencing a genome means determining the order in which the information, ie the genes, are placed in the genome, which allows obtaining information about the evolutionary line of organisms, which can bring new methods to diagnose diseases or formulate drugs and vaccines.
