DNA: how much DNA measures, what it is and what it is made of

DNA is present in all living organisms, from animals to plants and bacteria. Let’s find out how much DNA measures, what it is and what it is composed of, and why discovering it was a fundamental discovery for science.DNA: How much DNA measures, what it is and what it is composed ofDNA (which means ‘deoxyribonucleic acid’) is defined as “the great book of life.” In fact, this extraordinary molecule (that is, the smallest amount of a substance capable of preserving its chemical composition, determining its behavior and properties), is like a voluminous textbook. The structure of this “biological book” is very special and was discovered in Great Britain on February 28, 1953 thanks to the research of scientists James Watson (American), Francis Crick, Rosalind Franklin (British) and Maurice Wilkins (New Zealand). In practice, DNA contains all the information for define our most obvious characteristics such as the structure of our body, the color of the eyes, the color of the hair, etc. It is also full of very precise indications on how to make those complicated and highly efficient machines that are our cells work in every moment of our existence. And that is not all: DNA is also the precious “volume” that transmits generation information in generation, from parents to daughters and sons.How is it formed? DNA is composed of two strands in the form of a helix, joined together by the so-called nitrogenous bases, whose names are adenine (A), cytosine (C), guanine ( G) and thymine (T). These 4 bases form the alphabet with which the DNA book is written. The alphabet that we use goes from A to Z and has quite a few letters, the alphabet that DNA uses, on the other hand, includes only 4 letters: ACTG.In a DNA strand, the 4 nitrogenous bases succeed each other to form a very precise code that corresponds to specific information that regulates everything that happens inside the cell.The gene More specifically, a gene is the portion of DNA that contains specific ACGT sequences that provide the indications to create a precise cellular product, such as a protein (that is, an organic substance with a complex structure). If the DNA is the book, in short, the gene is the paragraph that contains all the indications to take to carry out a certain process in a living being, animal or plant. The information contained in the genes will then be transformed into concrete actions by real “skilled workers” who, based on the instructions given, will create a finished and functional product (for example, the proteins mentioned above), as in a highly efficient assembly line. In our cells, most of the DNA is enclosed within a specific part of the cell called the nucleus. In human cells, DNA is divided into 46 structures called chromosomes. In sex cells, which are the ovum and sperm, there are only 23 chromosomes: they will have 46 again after fertilization. A cell with 46 chromosomes can have 6 billion nitrogenous bases. This means that each cell contains within it about two meters of DNA enclosed in a microscopic space. But a curious fact is that if we aligned the content in all the cells of a man’s body, this incredible strand would be three trillion trillion meters long! Yes, you read that correctly:Each of us has enough DNA in our body to connect the Earth to the Sun (which is 150 million kilometers from us) more than 300 times! Or, if you prefer, wrap the Earth’s equator two and a half million times!