any cell in the body and all the peculiarities of the anatomical, morphological and functional structure determined proteins that are part of them.Hereditary characteristics of an organism is the ability to synthesis of certain proteins.The DNA molecule amino acids are located in the polypeptide chain, which determines the biological characteristics.
For each cell characterized by its sequence of nucleotides in a polynucleotide strand DNA.This is the genetic code of DNA.Through his written information about the synthesis of certain proteins.That is the genetic code of its properties and the genetic information covered in this article.
little history
idea that perhaps the genetic code, there was formulated Dzh.Gamovym A.Daunom and in the middle of the twentieth century.They describe that a sequence of nucleotides that is responsible for the synthesis of certain amino acids, comprising at least three links.Later proven accurate amount of three nucleotides (a unit of the genetic code), which is called a triplet or codon.In total there are sixty-four nucleotides, because acid molecule, where the RNA or protein synthesis, consists of four different nucleotide residues.
What is the genetic code
method of encoding the amino acid sequences of proteins, thanks to a nucleotide sequence common to all living cells and organisms.That's what the genetic code.
in DNA are four nucleotides:
- adenine - A;
- guanine - G;
- cytosine - C;
- thymine - T
These are indicated in capital letters or Latin (in Russian literature) Russian.
The RNA also contains four nucleotides, but one of them is different from the DNA:
- adenine - A;
- guanine - G;
- cytosine - C;
- uracil - US
All nucleotides arranged in a chain, in which the DNA double helix is obtained, and RNA - single.
proteins are based on the twenty amino acids, wherein they are arranged in a certain sequence determined by its biological properties.
properties of the genetic code
triplet.The unit of genetic code consists of three letters, it is a triplet.This means that existing twenty amino acids encoded by three specific nucleotides, called codons or trilpetami.There are sixty-four combinations that can be created from the four nucleotides.This is more than enough to encode the twenty amino acids.
degeneration.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 the information about the target hemoglobin beta triplet GAA and GAG encodes glutamic acid.And everyone who is sick sickle cell disease, a single nucleotide replaced.
collinear.The amino acid sequence always corresponds to the nucleotide sequence that contains the gene.
genetic code is continuous and compact, which means that it does not have a "punctuation."That is, starting at a particular codon is continuous readout.For example, AUGGUGTSUUAAUGUG be read as: AUG, GUG, TSUU, AAU, GUG.But not the AUG, UGG, etc. or else otherwise.
versatility.He is one absolutely for all terrestrial organisms, from humans to fish, fungi and bacteria.
Table
In the following table, there are not all the amino acids.Hydroxyproline, hydroxylysine, phosphoserine, iodo tyrosine, cystine, and some others are not available, because they are derived from other amino acids encoded by mRNA and the protein produced after modification as a result of translation.
from the properties of the genetic code is well known that one codon able to encode a single amino acid.The exception is the additional functions and encoding valine and methionine, the genetic code.MRNA is at the beginning with the codon attaches tRNA that carries formylmethionyl.Upon completion of synthesis, he splits himself and grabs for a formyl radical, transformed into methionine residue.Thus, the above codons are the initiators of the synthesis of polypeptide chain.If they are not at the beginning, it is no different from the others.
genetic information
Under this concept refers to the properties of the program, which is transmitted from the ancestors.It lies in the heredity genetic code.
implemented in the synthesis of protein genetic code of RNA (ribonucleic acid):
- information and RNA;
- transport tRNA;
- ribosomal rRNA.
information is sent direct dialing (DNA-RNA-protein) and reverse (Wednesday-protein-DNA).
Organisms can receive, store, transfer, and use it with the most effective.
passing on hereditary information determines the development of an organism.But because of the interaction with the environment reaction latest distorted, making and the evolution and development.Thus the body is laid in new information.
Calculation laws of molecular biology and the discovery of the genetic code illustrate what is necessary to connect genetics with Darwin's theory, which appeared on the basis of synthetic theory of evolution - non-classical biology.
heredity, variation and natural selection of Darwin selection complemented genetically determined.Evolution is implemented at the genetic level by random mutations and inheritance of the most valuable attributes that are most adapted to the environment.
Deciphering the code in humans
In the nineties, a project was launched Human Genome, resulting in two-thousand were discovered fragments of the genome, containing 99.99% of human genes.It remains unknown fragments that do not participate in protein synthesis and not encoded.Their role remains unknown.
last opened in 2006. Chromosome 1 is the longest in the genome.Over three hundred fifty diseases, including cancer, are the result of disturbances and mutations therein.
role of such research can not be overestimated.When opened, what the genetic code, it became known, on what is the development of laws, how a morphological structure, mentality, predisposition to certain diseases, metabolism and defects of individuals.
