Central dogma of molecular biology - is the flow of information from DNA through RNA on the protein : information is transferred from nucleic acids to proteins, but not vice versa. The rule was formulated by Francis Crick in 1958. The transfer of genetic information from DNA to RNA and from RNA to protein is universal for all cellular organisms without exception, and underlies the biosynthesis of macromolecules. Genome replication corresponds to the DNA → DNA informational transition. In nature, there are also transitions RNA → RNA and RNA → DNA (for example, in some viruses).
DNA, RNA and proteins are linear polymers, that is, each monomer they contain combines with a maximum of two other monomers. The sequence of monomers encodes information, the transmission rules of which are described by the central dogma.
General - found in most living organisms; Special - occurring as an exception, in viruses and in mobile elements of the genome or in the conditions of a biological experiment; Unknown - not found.
DNA replication (DNA → DNA)Transcription (DNA → RNA)Translation (RNA → protein) Mature mRNA is read by ribosomes during translation. Complexes of initiation and elongation factors deliver aminoacylated transfer RNAs to the mRNA-ribosome complex.
Reverse transcription (RNA → DNA) transfer of information from RNA to DNA, a process that is the reverse of normal transcription, carried out by the enzyme reverse transcriptase. Occurs in retroviruses such as HIV. RNA replication (RNA → RNA) copying an RNA chain to its complementary RNA chain using the enzyme RNA-dependent RNA polymerase. Viruses containing single-stranded (for example, foot-and-mouth disease virus) or double-stranded RNA replicate in a similar way. Direct translation of a protein on a DNA template (DNA → protein) Live translation has been demonstrated in E. coli cell extracts that contained ribosomes but no mRNA. Such extracts synthesized proteins from DNA introduced into the system, and the antibiotic neomycin enhanced this effect.
11. Types of matrix synthesis as a central process in the transmission, storage and implementation of hereditary material.
matrix the nature of the synthesis of nucleic acids and proteins provides high accuracy of information reproduction .
genetic information genotype defines phenotypic signs of a cell genotype transforms into phenotype .
This direction of information flow includes three typesmatrix syntheses:
1. DNA synthesis - replication
2. RNA synthesis - transcription
3. protein synthesis - broadcast
1) DNA replication (DNA → DNA) exact duplication (replication) of DNA. Replication is carried out by a complex of proteins that unwind the chromatin, then the double helix. After that, DNA polymerase and its associated proteins build an identical copy on each of the two strands. Playbacksource genetic material in generations.2) Transcription (DNA → RNA) the biological process by which the information contained in a piece of DNA is copied onto the synthesized mRNA molecule. Transcription is carried out by transcription factors and RNA polymerase. 3) Translation (RNA → protein) Genetic information is translated into polypeptide chains. Complexes of initiation factors and elongation factors deliver aminoacylated transfer RNAs to the mRNA-ribosome complex. 4) In special cases, RNA can be rewritten in the form of DNA (reverse transcription) and also copied in the form of RNA (replication), but a protein can never be a template for nucleic acids.
Repair- this is matrix synthesis that corrects errors in the structure of DNA , option limited replication. Restores initial structure of DNA. The matrix is a plot intact strands of DNA.
Structure of nucleotides. Spatial isomers (2'-endo-, 3'-endo-, etc., anti, syn)
NUCLEOTIDE- a complex chemical group found in the natural state. Nucleotides are the building blocks for NUCLEIC acids (DNA and RNA). Nucleotides are built from three components: a pyrimidine or purine base, pentose, and phosphoric acid. Nucleotides are linked together in a chain by a phosphodiester bond. It is formed due to the esterification of the OH group C-3` of the pentose of one nucleotide and the OH group of the phosphate residue of another nucleotide. As a result, one of the ends of the polynucleotide chain ends with a free phosphate (P-terminus or 5'-terminus). On the other end, there is a non-esterified OH group at C-3'pentose (3'-end). In living cells, free nucleotides are also found, presented in the form of various coenzymes, which include ATP. 
All 5 heterocyclic bases included in the constituent nucleic acids have a flat conformation, but this is energetically unfavorable. Therefore, 2 conformations are realized in polynucleotides C3`-endo and C2`-endo. C1, 0 and C4 are located in the same plane, C2 and C3 are in endo conformations when they are brought out above this plane, i.e. in the direction of communication С4-С5. 
The most important feature in determining the conformation of a nucleotide unit is the mutual arrangement of the carbohydrate and heterocyclic parts, which is determined by the angle of rotation around the N-glycosidic bond. There are 2 regions of allowed conformations, syn- and anti-.
All living things depend on three basic molecules for essentially all of their biological functions. These molecules are DNA, RNA and protein. Two strands of DNA rotate in opposite directions and are located next to each other (anti-parallel). This is a sequence of four nitrogenous bases directed along the backbone that encodes biological information. According to the genetic code, RNA strands are converted to determine the sequence of amino acids in proteins. These strands of RNA are originally made using strands of DNA as a template, a process called transcription.
Without DNA, RNA and proteins, no biological life would exist on Earth. DNA is an intelligent molecule that codes for the complete set of genetic instructions (the genome) needed to assemble, maintain and reproduce every living being. RNA plays multiple vital roles in encoding, decoding, regulating and expressing genetics. The main duty of RNA is to make proteins according to the instruction sets encoded in the cell's DNA.
DNA is made up of a sugar, a nitrogenous base, and a phosphate group. RNA is the same.
In DNA, the nitrogenous base is made up of nucleic acids: cytosine (C), guanine (G), adenine (A), and thymine (T). Metaphysically, each of these nucleic acids is associated with the elemental substances of the planet: Air, Water, Fire and Earth. When we pollute these four elements on Earth, we pollute the corresponding nucleic acid in our DNA.
However, in RNA, the nitrogenous base consists of nucleic acids: cytosine (C), guanine (G), adenine (A), and uracil (U). In addition, each of the RNA nucleic acids is associated with the elemental substances of the planet: Air, Water, Fire, and Earth. In both DNA and RNA, Mitochondrial DNA corresponds to the fifth basic element Cosmic Ether, outgoing t only from Mother. This is an example of allotropy, which is the property of a small number of chemical elements to be in two or more distinct forms, known as allotropes of those elements. Allotropes are various structural modifications of an element. Our DNA is an allotrope of the four basic planetary elements.
The main biological function of the nitrogenous bases in DNA is to link nucleic acids. Adenine always combines with thymine, and guanine always combines with cytosine. They are known as paired bases. Uracil is present only in RNA, replacing thymine and combining with adenine.
Both RNA and DNA use base pairing (male + female) as an additional language that can be converted in either direction between DNA and RNA by the action of the appropriate enzymes. This male-female language or base pairing structure provides a back-up copy of all the genetic information encoded within double stranded DNA.
Reverse twin base
All DNA and RNA function on the gender principle of base pairing, creating a hydrogen bond. Paired bases must join in sequence, allowing DNA and RNA to interact (according to the original design of our 12 Strands of DNA, the Diamond Sun Body) and also allowing RNA to produce functioning proteins that build the links that synthesize and repair the DNA double helix. Human DNA has been damaged by base-pair mutation and alteration of sequence editing pairs or inserts by engineered organisms such as a virus. Intervention in the paired bases concerns the technology of the gender split of the reverse network of Nephilim (NRG), influencing all male and female language and their relationships. Copies of DNA are created by joining nucleic acid subunits with a male-female base pair on each strand of the original DNA molecule. Such a connection always occurs in certain combinations. Alteration of the basic DNA compound, as well as many levels of genetic modification and genetic control, contribute to the suppression of DNA synthesis. This is a deliberate suppression of the activation of the 12 DNA strands of the original blueprint, the Silicon Matrix, assembled and built by proteins. This genetic suppression has been carried out aggressively since the cataclysm of Atlantis. It is directly related to the suppression of the union of hierogamy, which is achieved by the correct connection of the DNA bases, with which it is possible to create and assemble proteins to restore the fire letters of DNA.
RNA editing with aspartame
One example of genetic modification and experimentation with the population is the use of aspartame*. Aspartame is chemically synthesized from aspartate, which impairs the function of the uracil-thymine bond in DNA, and also reduces the functions of RNA protein synthesis and communication between RNA and DNA. RNA editing through the addition or removal of uracil and thymine recoded the cell's mitochondria, in which mitochondrial damage contributed to neurological disease. Thymine is a powerful protector of DNA integrity. In addition, lowering uracil produces the substrate aspartate, carbon dioxide and ammonia.
Interference with the nitrogen cycle
As a result of the Industrial Revolution, the deployment of the military complex through NEA contacts, the overall nitrogen cycle has been significantly altered over the past century. While nitrogen is essential for all known life on Earth, there have been fossil fuel wars deliberately forced by the NAA, polluting the Earth and damaging DNA. Nitrogen is a component of all amino acids that make up proteins and is present in the bases that make up the nucleic acids of RNA and DNA. However, by waging wars over fossil fuels, forcing the use of internal combustion engines, the creation of chemical fertilizers, and the pollution of the environment by vehicles and industries, people have contributed to serious nitrogen toxicity in biological forms. Nitric oxide, carbon dioxide, methane, ammonia - all this creates a greenhouse gas that poisons the Earth, drinking water and oceans. This contamination causes DNA damage and mutation.
Elemental Change of the Pain Body
Thus, many of us have experienced elemental changes in our blood, body parts (especially on the surface of the skin that responds to changes in blood) and profound changes in our cells and tissues. The revitalization of matter as a result of magnetic changes also penetrates the levels of our emotional-elemental body, significantly affecting the cellular reactions and memory stored in the Instinctive Body (Pain Body).
This new cycle forces each of us to pay attention to our instinctive body, our emotional-elemental pain body, and what is happening to it. The relationship of solar and lunar forces and their combined effect on the polarities of the planetary body forces are adjusted to this effect on the magnetic field.
Unfortunately, failure to understand the higher principles of Natural Law results in great chaos and suffering for those who persist in indulging in destruction, division and violence, regardless of the methods used.
However, the massive exodus of lunar forces, lunar chain beings, Fallen Angels from our planet and solar system continues at this time. As the solar system is quarantined, those who are Ascended (or pure of heart) will experience a profound realignment of their sacred energy centers from lunar to solar influences. This bifurcation of solar and lunar forces continues to change not only in the emotional-elemental body, but also in the sacral center and all reproductive organs. It brings adjustments or insights to many of the issues related to sexual suffering that have been programmed based on the hidden histories associated with the lunar chain entities. Mother's magnetic command sets and mitochondrions restore the Solar Femininity for their earthly children as well.
DNA synthesis
Understanding that our emotional-elemental body moves from carbon-based atoms to higher-based elements through high frequency activation and planetary magnetic changes, we can connect the dots in the spiritual development of our own bodies associated with personal alchemical processes. In the restoration of the sophianic body, the alchemical transformation of our evolution of consciousness merges with the scientific understanding of DNA synthesis. DNA synthesis is as important as DNA activation, which plays an important and direct role in spiritual ascension. The Mother brings back the mitochondrial DNA record through the reversal of magnetic currents, restoring the blueprint of our blood, brain and nervous system to higher functioning with our true original DNA.
*BUT spartam is a genetically engineered chemical distributed and marketed as a dietary supplement
Translation: Oreanda Web
In 1975, Howard Temin and David Baltimore independently discovered reverse transcription. It turned out that there is an enzyme reversetase that synthesizes DNA on an RNA template. They received the Nobel Prize for this discovery.
Another discovery related to our topic (and also awarded the Nobel Prize) was made in 1989 by Sydney Altman and Thomas Check. It turned out that RNA can perform an enzymatic function. Altman and Check found that the RNA molecule itself is able to “bite off” a piece of itself, and for this it does not need any proteins. Later, other, more complex forms of RNA catalytic activity were found. RNA enzymes were called ribozymes (by analogy with protein enzymes, enzymes). It should be noted that DNA can also work as a deoxyribozyme, but there are far fewer such experiments than experiments with ribozymes.
Let us dwell once again on the interaction of proteins and RNA, in particular, on the provision of processes occurring in the cell.
I must say that RNAs work somewhat slower than proteins, and in some enzymes RNAs do the main work, and proteins help it, that is, without proteins, it does its job much worse, but nevertheless it can work without proteins. When ribozymes were discovered, biologists began to place RNA at the center of thinking about the origin of life and the early stages of the evolution of life. First, RNA is a nucleic acid that can form complementary bonds, that is, it can be replicated. There are viruses that contain RNA that replicates, these viruses have a special RNA replicase enzyme. That is, RNA can perform the function of replication, it can also perform the enzymatic function, that is, it can work as an RNA genome and as an RNA enzyme.
The hypothesis that RNA could have arisen before DNA and proteins has been called the RNA world. Now this is considered a generally accepted fact in many textbooks, although, strictly speaking, other scenarios for the development of life cannot be ruled out. The hypothesis explains a lot, much more than other hypotheses. The hypothesis that proteins lie at the origins of life is less rational, since it is also necessary to look for the answer to the question why proteins that self-replicated then lost this ability?
The RNA world hypothesis does not speak of the very beginning of the emergence of living molecules on Earth, it speaks of the next stage of evolution, when biomolecules exist, there are some processes, but the world is not yet the same as it is now, to which we are accustomed. There is no DNA in that world yet, apparently there are no proteins either, although there are already amino acids and oligopeptides, there is no translation process, but there is a transcription process, only RNA is synthesized not on DNA, but on RNA. There is an RNA genome on which a working molecule of the RNA enzyme is synthesized. Some authors, trying to reconstruct the features of this world, suggest that tRNA is a relic of the RNA world, and that the RNA genome was similar to tRNA. tRNA molecules are involved not only in the biosynthesis of proteins as carriers of amino acids, but also participate in other processes, including regulatory ones. It is assumed that the three nucleotides that are located in the anticodon were a label for the genome, but these nucleotides were not in the working RNA molecule. Working copies of RNA molecules could be destroyed during operation, and they did not need to be used for replication. The tagged RNA genome was a template for the synthesis of many working molecules, and when RNA needs to be replicated, this tag is used to find out which molecule needs to be replicated, a copy is formed along with the tag, and a new genomic RNA is formed from this tag. We emphasize that this is only a hypothesis and so far it cannot be proved, although there are some indications that such processes could take place.
The next process to appear is translation. Proteins began to be synthesized on RNA and there are many hypotheses about how and why this happened and why it was beneficial. It is believed that DNA was the last to appear. Since RNA is less stable, DNA began to perform the functions of the genome, and RNA retained only a part of the functions that it had in the RNA world. DNA copies of RNA molecules could have arisen in the process of reverse transcription. But in order to read information from DNA, the process of transcription had to appear. Perhaps, at first, for DNA replication, it was required to translate it into an RNA copy, and then synthesize new DNA by reverse transcription. But at some stage, DNA replication without an RNA messenger should have appeared. True, we still cannot do without RNA - let me remind you that DNA polymerase requires an RNA primer to initiate DNA synthesis.
The proposed order of appearance of living functions is as follows: catalytic functions of ribozymes and RNA replication, then translation is added, then reverse transcription and transcription of RNA to DNA are added, after that DNA replication. DNA compaction arose later than anything (I remind you that we spoke at one of the lectures about histone proteins and nucleosomes, which provide compaction in a eukaryotic cell). Compaction of DNA has made it possible to increase the size of the genome.
It is interesting to note that, since in all living organisms from bacteria, viruses to humans, one genetic code is used and the basic metabolic processes are similar. It is believed that all living organisms descended from one common ancestor. A common ancestor is a collection of cells and subcellular structures. It would be more accurate to say that the common ancestor was a collection of metabolic processes and the catalysts that regulate them.
This common ancestor, which had all the main systems of modern organisms (DNA, RNA, protein), is called progenot (progenitor). Next came evolution, which is more understandable how to study. On account of what happened before, you can only build hypotheses, but these hypotheses must be substantiated. For example, there are works that try to reconstruct the metabolism of the RNA world. How do they do it? At the beginning, they study the metabolic processes of a modern cell and try to find relics of the RNA world in them. That is, if we imagine that the RNA world existed, then the modern metabolism was “written” on top of the one that existed then. For example, we know that ATP works as a phosphorus donor, but other molecules can also be phosphorus donors. Why then save a molecule containing a ribonucleic part? It is believed that this is just a relic of the RNA world. Not only ATP has functions parallel to other substances, but also many ribonucleic co-factors, that is, compounds involved in enzymatic reactions, serving as intermediaries, "helpers" in the work of enzymes. For example, NADP - nicotinamide dinucleotide phosphate, etc. If some processes take place with the participation of co-factors that include a piece of RNA, and the same processes can take place in other organisms or in other parts of the cell without the participation of this ribo-piece, that is there is another donor of the phosphorus group or a donor of the methyl group, it is assumed that where the co-factor with the RNA component is a relic of the RNA world. And, having done such an analysis, they found processes that could be represented in the RNA world. An interesting feature is that the synthesis of fatty acids, presumably, was not represented in the list of such processes, because this requires mandatory protein components, which did not exist then.
An interesting question is whether the ribo-organism was engaged in oxygen photosynthesis? After all, oxygen appeared in the atmosphere 2 billion years ago, there was a change in the oxygen-free atmosphere to oxygen. If the reconstruction shows that oxygen photosynthesis could take place in the ribo-organism, then this would mean that ribo-organisms lived 2-3 billion years ago, and at that time there are already quite noticeable traces of prokaryotic cell structures in sedimentary rocks, and then it is possible to assume that they were left not by DNA organisms, but by RNA organisms.
We talked about the stages of development of life on earth, we said that first prokaryotes appeared, then eukaryotes, multicellular organisms, then social organisms, then human society. The question is sometimes asked: why do bacteria still exist? Why did more perfect organisms (eukaryotes) not supplant prokaryotes. In fact, eukaryotes cannot live without prokaryotes, because eukaryotes originated on Earth, where bacteria already lived, they are built into this system. Eukaryotes eat bacteria, consume what the bacteria have made, they are adapted to exactly the life that the bacteria have created for them. If prokaryotes are removed, then the foundation of life on Earth will collapse. Each new, more complex integrative level of life arose on the basis of the already established previous system, adapted to it, and could no longer exist without it.
The diversity of bacteria is great, they use very different chemical reactions as energy sources. Essentially, all geochemical cycles in the modern biosphere are controlled mainly by bacteria. Now they are running some key reactions, like the iron cycle, the sulfur cycle, nitrogen fixation. No one, except bacteria, can get nitrogen from the atmosphere and include it in their own molecules.
The genetic information is contained in DNA chromosomes in the cell nucleus. However, protein synthesis, the process in which the information encoded in a gene is used to determine the functions of a cell, takes place in the cytoplasm. This division reflects the fact that humans are eukaryotes. Human cells have a true nucleus containing the genome separated from the cytoplasm by a nuclear membrane. In prokaryotes, such as Escherichia coli, DNA is not isolated in the nucleus.
because of compartmentalization(separation) of eukaryotic cells, the transfer of information from the nucleus to the cytoplasm is a complex process that causes close attention of molecular and cellular biologists.
The molecular intermediary between the two types of information - the genetic code and the amino acid code of proteins - is ribonucleic acid (RNA). The chemical structure of RNA is similar to that of DNA, except that each RNA nucleotide has a carbohydrate component of ribose instead of deoxyribose; in addition, one of the pyrimidine bases of RNA contains uracil (U) instead of thymine. Another difference between RNA and DNA is that RNA in most organisms exists as a single molecule while DNA exists in the form of a double helix.
Information relations between DNA, RNA and protein are closely intertwined: based on genomic DNA the RNA sequence is directly synthesized, and on its basis the sequence of polypeptides is synthesized. Specific proteins are involved in the synthesis and metabolism of DNA and RNA. This flow of information is called the central dogma of molecular biology.
Genetic information is stored in the DNA of the genome in the form of a code (the genetic code is discussed below), in which the sequence of adjacent bases determines the sequence of amino acids in the polypeptide. First, RNA is synthesized from the DNA template, a process known as transcription. The RNA carrying the encoded information, the so-called messenger RNA (mRNA), moves from the nucleus to the cytoplasm, where the mRNA sequence is decoded (translated), determining the amino acid sequence in the synthesized protein.
Process translation(translation) occurs in ribosomes, which are cytoplasmic organelles with recognition sites for all involved molecules, including mRNAs involved in protein synthesis. Ribosomes are built from many different structural proteins and a specialized type of RNA known as ribosomal RNA (rRNA). Translation uses another, third type of RNA, transfer RNA (tRNA), which provides a molecular link between the codes contained in the mRNA base sequence and the amino acid sequence of the encoded protein.
Due to interdependent flow information represented by the central dogma, it is possible to discuss the molecular genetics of gene expression at any of the three informational levels: DNA, RNA, or protein. We begin by examining the structure of genes in the genome as a basis for discussing the genetic code, transcription, and translation.
The time in which we live is marked by amazing changes, huge progress, when people receive answers to more and more new questions. Life is rapidly moving forward, and what until recently seemed impossible is beginning to come true. It is quite possible that what seems today to be a plot from the science fiction genre will soon also acquire the features of reality.
One of the most important discoveries in the second half of the twentieth century was the nucleic acids RNA and DNA, thanks to which man came closer to unraveling the mysteries of nature.
Nucleic acids
Nucleic acids are organic compounds with high molecular weight properties. They include hydrogen, carbon, nitrogen and phosphorus.
They were discovered in 1869 by F. Misher, who investigated pus. However, at that time his discovery was not given much importance. Only later, when these acids were found in all animal and plant cells, did the understanding of their enormous role come.
There are two types of nucleic acids: RNA and DNA (ribonucleic and deoxyribonucleic acids). This article is devoted to ribonucleic acid, but for a general understanding, we will also consider what DNA is.
What
DNA is made up of two strands that are connected according to the law of complementarity by hydrogen bonds between nitrogenous bases. Long chains are twisted into a spiral, one turn contains almost ten nucleotides. The diameter of the double helix is two millimeters, the distance between nucleotides is about half a nanometer. The length of one molecule sometimes reaches several centimeters. The length of DNA in the nucleus of a human cell is almost two meters.
The structure of DNA contains all DNA possesses replication, which means the process during which two completely identical daughter molecules are formed from one molecule.
As already noted, the chain is made up of nucleotides, which, in turn, consist of nitrogenous bases (adenine, guanine, thymine and cytosine) and a phosphorus acid residue. All nucleotides differ in nitrogenous bases. Hydrogen bonding does not occur between all bases; adenine, for example, can only combine with thymine or guanine. Thus, there are as many adenyl nucleotides in the body as thymidyl nucleotides, and the number of guanyl nucleotides is equal to cytidyl nucleotides (Chargaff's rule). It turns out that the sequence of one chain predetermines the sequence of another, and the chains seem to mirror each other. Such a pattern, where the nucleotides of two chains are arranged in an orderly manner, and are also connected selectively, is called the principle of complementarity. In addition to hydrogen compounds, the double helix also interacts hydrophobically.
The two chains are in opposite directions, that is, they are located in opposite directions. Therefore, opposite the three "-end of one is the five"-end of the other chain.
Outwardly, it resembles a spiral staircase, the railing of which is a sugar-phosphate backbone, and the steps are complementary nitrogen bases.
What is ribonucleic acid?
RNA is a nucleic acid with monomers called ribonucleotides.
In chemical properties, it is very similar to DNA, since both are polymers of nucleotides, which are a phosphorylated N-glycoside that is built on a pentose (five-carbon sugar) residue, with a phosphate group at the fifth carbon atom and a nitrogen base at the first carbon atom.
It is a single polynucleotide chain (except for viruses), which is much shorter than that of DNA.
One RNA monomer is the residues of the following substances:
- nitrogen bases;
- five-carbon monosaccharide;
- phosphorus acids.
RNAs have pyrimidine (uracil and cytosine) and purine (adenine, guanine) bases. Ribose is the monosaccharide of the RNA nucleotide.
Differences between RNA and DNA
Nucleic acids differ from each other in the following properties:
- its quantity in the cell depends on the physiological state, age and organ affiliation;
- DNA contains the carbohydrate deoxyribose, and RNA contains ribose;
- the nitrogenous base in DNA is thymine, and in RNA it is uracil;
- classes perform different functions, but are synthesized on the DNA matrix;
- DNA is made up of a double helix, while RNA is made up of a single strand;
- it is uncharacteristic of acting in DNA;
- RNA has more minor bases;
- chains vary greatly in length.
History of study
The RNA cell was first discovered by a German biochemist R. Altman while studying yeast cells. In the middle of the twentieth century, the role of DNA in genetics was proven. Only then were RNA types, functions, and so on described. Up to 80-90% of the mass in the cell falls on rRNA, which together with proteins form the ribosome and participate in protein biosynthesis.
In the sixties of the last century, it was first suggested that there must be a certain species that carries the genetic information for protein synthesis. After that, it was scientifically established that there are such informational ribonucleic acids representing complementary copies of genes. They are also called messenger RNA.
The so-called transport acids are involved in decoding the information recorded in them.
Later, methods began to be developed for identifying the nucleotide sequence and establishing the structure of RNA in the acid space. So it was found that some of them, which were called ribozymes, can cleave polyribonucleotide chains. As a result, they began to assume that at the time when life was born on the planet, RNA acted without DNA and proteins. Moreover, all transformations were carried out with her participation.
The structure of the ribonucleic acid molecule
Almost all RNAs are single chains of polynucleotides, which, in turn, consist of monoribonucleotides - purine and pyrimidine bases.
Nucleotides are denoted by the initial letters of the bases:
- adenine (A), A;
- guanine (G), G;
- cytosine (C), C;
- uracil (U), U.
They are interconnected by three- and five-phosphodiester bonds.
A very different number of nucleotides (from several tens to tens of thousands) is included in the structure of RNA. They can form a secondary structure consisting mainly of short double-stranded strands that are formed by complementary bases.
Structure of a ribnucleic acid molecule
As already mentioned, the molecule has a single-stranded structure. RNA receives its secondary structure and shape as a result of the interaction of nucleotides with each other. It is a polymer whose monomer is a nucleotide consisting of a sugar, a phosphorus acid residue and a nitrogen base. Outwardly, the molecule is similar to one of the DNA chains. Nucleotides adenine and guanine, which are part of RNA, are purine. Cytosine and uracil are pyrimidine bases.
Synthesis process
In order for an RNA molecule to be synthesized, the template is a DNA molecule. True, the reverse process also happens, when new molecules of deoxyribonucleic acid are formed on the ribonucleic acid matrix. This occurs during the replication of certain types of viruses.
Other molecules of ribonucleic acid can also serve as a basis for biosynthesis. Its transcription, which occurs in the cell nucleus, involves many enzymes, but the most significant of them is RNA polymerase.
Kinds
Depending on the type of RNA, its functions also differ. There are several types:
- informational i-RNA;
- ribosomal r-RNA;
- transport t-RNA;
- minor;
- ribozymes;
- viral.
Information ribonucleic acid
Such molecules are also called matrix. They make up about two percent of the total in the cell. In eukaryotic cells, they are synthesized in the nuclei on DNA templates, then passing into the cytoplasm and binding to ribosomes. Further, they become templates for protein synthesis: they are joined by transfer RNAs that carry amino acids. This is how the process of information transformation takes place, which is realized in the unique structure of the protein. In some viral RNAs, it is also a chromosome.
Jacob and Mano are the discoverers of this species. Not having a rigid structure, its chain forms curved loops. Not working, i-RNA gathers into folds and folds into a ball, and unfolds in working condition.
The mRNA carries information about the sequence of amino acids in the protein that is being synthesized. Each amino acid is encoded in a specific place using genetic codes, which are characterized by:
- triplet - from four mononucleotides it is possible to build sixty-four codons (genetic code);
- non-crossing - information moves in one direction;
- continuity - the principle of operation is that one mRNA is one protein;
- universality - one or another type of amino acid is encoded in all living organisms in the same way;
- degeneracy - twenty amino acids are known, and sixty-one codons, that is, they are encoded by several genetic codes.
Ribosomal ribonucleic acid
Such molecules make up the vast majority of cellular RNA, namely eighty to ninety percent of the total. They combine with proteins and form ribosomes - these are organelles that perform protein synthesis.
Ribosomes are sixty-five percent rRNA and thirty-five percent protein. This polynucleotide chain easily bends along with the protein.
The ribosome consists of amino acid and peptide regions. They are located on contact surfaces.
Ribosomes move freely to the right places. They are not very specific and can not only read information from mRNA, but also form a matrix with them.
Transport ribonucleic acid
tRNAs are the most studied. They make up ten percent of cellular ribonucleic acid. These types of RNA bind to amino acids thanks to a special enzyme and are delivered to ribosomes. In this case, amino acids are carried by transport molecules. However, it happens that different codons code for an amino acid. Then several transport RNAs will carry them.
It curls up into a ball when inactive, and when functioning, has the appearance of a clover leaf.
It contains the following sections:
- an acceptor stem having an ACC nucleotide sequence;
- site for attachment to the ribosome;
- an anticodon encoding the amino acid that is attached to this tRNA.
Minor species of ribonucleic acid
Recently, RNA species have been replenished with a new class, the so-called small RNAs. They are most likely universal regulators that turn genes on or off in embryonic development, and also control processes within cells.
Ribozymes have also recently been identified, they are actively involved when the RNA acid is fermented, acting as a catalyst.
Viral types of acids
The virus is capable of containing either ribonucleic acid or deoxyribonucleic acid. Therefore, with the corresponding molecules, they are called RNA-containing. When such a virus enters a cell, reverse transcription occurs - new DNA appears on the basis of ribonucleic acid, which are integrated into cells, ensuring the existence and reproduction of the virus. In another case, the formation of complementary RNA occurs on the incoming RNA. Viruses are proteins, vital activity and reproduction goes on without DNA, but only on the basis of the information contained in the RNA of the virus.
replication
In order to improve the overall understanding, it is necessary to consider the process of replication, which results in two identical nucleic acid molecules. This is how cell division begins.
It involves DNA polymerases, DNA-dependent, RNA polymerases and DNA ligases.
The replication process consists of the following steps:
- despiralization - there is a sequential unwinding of the maternal DNA, capturing the entire molecule;
- breakage of hydrogen bonds, in which the chains diverge, and a replication fork appears;
- adjustment of dNTPs to the released bases of maternal chains;
- cleavage of pyrophosphates from dNTP molecules and the formation of phosphorodiester bonds due to the released energy;
- respiration.
After the formation of the daughter molecule, the nucleus, cytoplasm and the rest are divided. Thus, two daughter cells are formed that have completely received all the genetic information.
In addition, the primary structure of proteins that are synthesized in the cell is encoded. DNA takes an indirect part in this process, and not direct, which consists in the fact that it is on DNA that the synthesis of proteins, RNA involved in the formation, takes place. This process is called transcription.
Transcription
The synthesis of all molecules occurs during transcription, that is, the rewriting of genetic information from a specific DNA operon. The process is similar in some ways to replication, and in others it is very different.
Similarities are the following parts:
- the beginning comes from the despiralization of DNA;
- there is a break in the hydrogen bonds between the bases of the chains;
- NTFs are complementarily adjusted to them;
- hydrogen bonds are formed.
Differences from replication:
- during transcription, only the section of DNA corresponding to the transcripton is untwisted, while during replication, the entire molecule is untwisted;
- during transcription, tunable NTPs contain ribose, and instead of thymine, uracil;
- information is written off only from a certain area;
- after the formation of the molecule, the hydrogen bonds and the synthesized strand are broken, and the strand slips off the DNA.
For normal functioning, the primary structure of RNA should consist only of DNA sections written off from exons.
The newly formed RNA begins the process of maturation. Silent regions are excised, and informative regions are fused to form a polynucleotide chain. Further, each species has transformations inherent only to it.
In mRNA, attachment to the initial end occurs. Polyadenylate joins the final site.
Bases are modified in tRNA to form minor species.
In r-RNA, individual bases are also methylated.
Protect from destruction and improve the transport of proteins into the cytoplasm. RNA in the mature state are connected to them.
Significance of deoxyribonucleic and ribonucleic acids
Nucleic acids are of great importance in the life of organisms. They store, transfer to the cytoplasm and inherit to daughter cells information about the proteins synthesized in each cell. They are present in all living organisms, the stability of these acids plays an important role for the normal functioning of both cells and the whole organism. Any changes in their structure will lead to cellular changes.
