What is a genetic code: general information

In any cell and organism, all features of anatomical, morphological and functional character are determined by the structure of proteins that enter into them. Hereditary property of the organism is the ability to synthesize certain proteins. In the DNA molecule, amino acids are located in the polypeptide chain, on which biological signs depend.
Each cell has its own sequence of nucleotides in the DNA polynucleotide chain. This is the genetic code of DNA. Through it, information is recorded on the synthesis of certain proteins. About what the genetic code, about its properties and genetic information is told in this article.

A bit of history

The idea that, perhaps, a genetic code exists, was formulated by J. Gamow and A. Daun in the middle of the twentieth century. They described that the nucleotide sequence responsible for the synthesis of a particular amino acid contains at least three links. Later, they proved the exact number of three nucleotides (this is a unit of the genetic code), which was called a triplet or codon. There are sixty-four nucleotides in total, because the molecules of acids where the protein or RNA is synthesized consist of the residues of four different nucleotides.

What is the genetic code

The method for encoding a sequence of amino acid proteins due to the nucleotide sequence is characteristic of all living cells and organisms. That's what the genetic code is.
There are four nucleotides in DNA:

• Adenine - A;
• Guanine-G;
• Cytosine-C;
• Thymine - T.

They are denoted by capital letters in Latin or (in Russian-language literature) by Russians.
RNA also contains four nucleotides, but one of them differs from DNA:

• Adenine - A;
• Guanine-G;
• Cytosine-C;
• Uracil - U.

All nucleotides are aligned in chains, with a double helix in DNA and a single helix in RNA.
Proteins are built on twenty amino acids, where they, located in a certain sequence, determine its biological properties.

Genetic Code Properties

The triplet. The unit of the genetic code consists of three letters, it is a triplet. This means that the twenty existing amino acids are enciphered by three specific nucleotides, which are called codons or trilpites. There are sixty-four combinations that can be created from four nucleotides. This amount is more than enough to encode twenty amino acids.
Degeneracy. Each amino acid corresponds to more than one codon, with the exception of methionine and tryptophan.
Uniqueness. One codon encodes one amino acid. For example, in the gene of a healthy person with information about the beta-target of hemoglobin, the triplet of GAG and GAA codes for glutamic acid. And for all who are sick with sickle cell disease, one nucleotide is replaced.
Collinearity. The amino acid sequence always corresponds to the nucleotide sequence that the gene contains.
The genetic code is continuous and compact, which means that it does not have "punctuation marks". That is, starting at a certain codon, there is a continuous reading. For example, AUGGUGTSUUAAUGUG will be read as: AUG, GUG, TSUU, AAU, GUG. But it's not AUG, UGG, and so on, or somehow else.
Versatility. It is unique for all terrestrial organisms, from humans to fish, fungi and bacteria.

Table

In the table presented, not all available amino acids are present. Hydroxyproline, hydroxylizine, phosphoserine, iodo derivatives of tyrosine, cystine and some others are absent, since they are derivatives of other amino acids encoded by mRNA and formed after modification of proteins as a result of translation.
From the properties of the genetic code, it is known that one codon is capable of encoding one amino acid. An exception is performing additional functions and encoding valine and methionine, a genetic code. The mRNA, when in the beginning with the codon, attaches tRNA, which carries formylmethion. Upon completion of the synthesis, it cleaves itself and captures the formyl residue behind it, converting it into a methionine residue. Thus, the aforementioned codons are the initiators of the synthesis of a chain of polypeptides. If they are not in the beginning, then they are no different from the others.

Genetic information

By this concept is meant a program of properties that is transmitted from ancestors. It is inherent in geneticity as a genetic code.
The genetic code of RNA (ribonucleic acids) is realized during protein synthesis:

• Information-and-RNA;
• Transport tRNA;
• Ribosomal p-RNA.

Information is transmitted by a direct link (DNA-RNA-protein) and reverse (medium-protein-DNA).
Organisms can receive, store, transmit and use it most effectively.
Transmitted by inheritance, information determines the development of a particular organism. But because of interaction with the environment, the reaction of the latter is distorted, due to which the evolution and development takes place. Thus, new information is inserted into the body.

The calculation of the laws of molecular biology and the discovery of the genetic code illustrated that it is necessary to connect genetics with Darwin's theory, on the basis of which a synthetic theory of evolution, nonclassical biology, emerged.
Heredity, variability and natural selection of Darwin are supplemented by genetically determined selection. Evolution is realized at the genetic level through random mutations and by inheriting the most valuable traits that are most adapted to the environment.

Decoding of the code in humans

In the nineties, the Human Genome project was launched, as a result of which genome fragments containing 99.99% of human genes were discovered in two thousandths. The fragments that are not involved in the synthesis of proteins and are not coded remain unknown. Their role remains unknown.

The last chromosome 1 discovered in 2006 is the longest in the genome. More than three hundred and fifty diseases, including cancer, appear as a result of disorders and mutations in it.

The role of such studies is difficult to overestimate. When they discovered what a genetic code is, it became known, according to what laws develops, how the morphological structure, the psyche, the predisposition to certain diseases, the metabolism and the vices of individuals are formed.