To maintain life in a living organism, many processes occur. We can observe some of them - breathing, eating, getting rid of waste products, receiving information through the senses and forgetting this information. But most of the chemical processes are hidden from view.
Reference. Classification
In scientific terms, metabolism is metabolism.
Metabolism is usually divided into two stages:during catabolism, complex organic molecules break down into simpler ones to produce energy; (energy is wasted)
In the processes of anabolism, energy is spent on the synthesis of complex biomolecules from simple molecules. (energy is stored)
Biomolecules, as seen above, are divided into small molecules and large ones.
Small:Lipids (fats), phospholipids, glycolipids, sterols, glycerolipids,
Vitamins
Hormones, neurotransmitters
Metabolites
Large:
Monomers, oligomers and polymers.
Monomers Oligomers Biopolymers
Amino acids Oligopeptides Polypeptides, proteinsMonosaccharides Oligosaccharides Polysaccharides (starch, cellulose)
Nucleotides Oligonucleotides Polynucleotides, (DNA, RNA)
The biopolymers column contains polynucleotides. This is where ribonucleic acid is located - the object of the article.
Ribonucleic acids. Structure, purpose.
The figure shows an RNA molecule.
Nucleic acids DNA and RNA are present in the cells of all living organisms and perform the functions of storing, transmitting and implementing hereditary information.
Similarities and differences between RNA and DNA
As you can see, there is an external resemblance to the known structure of the DNA molecule (deoxyribonucleic acid).However, RNA can have either a double-stranded or single-stranded structure.
Nucleotides (pentagons and hexagons in the figure)
In addition, the RNA strand consists of four nucleotides (or nitrogenous bases, which are the same thing): adenine, uracil, guanine and cytosine.
The DNA strand consists of another set of nucleotides: adenine, guanine, thymine and cytosine.
Chemical structure of RNA polynucleotide:
As you can see, there are characteristic nucleotides uracil (for RNA) and thymine (for DNA).
All 5 nucleotides in the picture:
The hexagons in the pictures are benzene rings, into which, instead of carbon, other elements are embedded, in this case, nitrogen.
Benzene. For reference.
The chemical formula of benzene is C6H6. Those. Each corner of a hexagon contains a carbon atom. The 3 additional inner lines in the hexagon indicate the presence of double covalent bonds between these carbon atoms. Carbon is an element of group 4 of the periodic table, therefore, it has 4 electrons that can form a covalent bond. In the figure there is one bond with a hydrogen electron, a second with a carbon electron on the left, and 2 more with 2 carbon electrons on the right. However, physically there is a single electron cloud covering all 6 carbon atoms of benzene.
Compounding nitrogenous bases
Complementary nucleotides link to each other (hybridize) using hydrogen bonds. Adenine is complementary to uracil, and guanine is complementary to cytosine. The longer the complementary regions on a given RNA, the stronger the structure they form will be; on the contrary, short sections will be unstable. This determines the function of a particular RNA.The figure shows a fragment of the complementary region of RNA. Nitrogen bases are colored blue
RNA structure
The linkage of many groups of nucleotides is formed by RNA hairpins (primary structure):
Many pins in the tape interlock to form a double helix. When expanded, this structure resembles a tree (Secondary structure):
The spirals also interact with each other (tertiary structure). You can see how different spirals are connected to each other:
Other RNAs fold similarly. Resembles a set of ribbons (quaternary structure).
Conclusion
To calculate the conformations that RNA will adopt based on their primary sequence, there areWhat are DNA and RNA? What are their functions and significance in our world? What are they made of and how do they work? This and more is discussed in the article.
What are DNA and RNA
Biological sciences that study the principles of storage, implementation and transmission of genetic information, the structure and functions of irregular biopolymers belong to molecular biology.
Biopolymers, high-molecular organic compounds that are formed from nucleotide residues, are nucleic acids. They store information about a living organism, determine its development, growth, and heredity. These acids are involved in protein biosynthesis.
There are two types of nucleic acids found in nature:
- DNA - deoxyribonucleic;
- RNA is ribonucleic.
The world was told what DNA is in 1868, when it was discovered in the cell nuclei of leukocytes and salmon sperm. They were later found in all animal and plant cells, as well as in bacteria, viruses and fungi. In 1953, J. Watson and F. Crick, as a result of X-ray structural analysis, built a model consisting of two polymer chains that are twisted in a spiral around one another. In 1962, these scientists were awarded the Nobel Prize for their discovery.
Deoxyribonucleic acid
What is DNA? This is a nucleic acid that contains the genotype of an individual and transmits information by inheritance, self-reproducing. Because these molecules are so large, there are a huge number of possible nucleotide sequences. Therefore, the number of different molecules is virtually infinite.
DNA structure
These are the largest biological molecules. Their size ranges from one quarter in bacteria to forty millimeters in human DNA, much larger than the maximum size of a protein. They consist of four monomers, the structural components of nucleic acids - nucleotides, which include a nitrogenous base, a phosphoric acid residue and deoxyribose.
Nitrogen bases have a double ring of carbon and nitrogen - purines, and one ring - pyrimidines.
Purines are adenine and guanine, and pyrimidines are thymine and cytosine. They are designated by capital Latin letters: A, G, T, C; and in Russian literature - in Cyrillic: A, G, T, Ts. Using a chemical hydrogen bond, they connect with each other, resulting in the appearance of nucleic acids.
In the Universe, the spiral is the most common shape. So the structure of the DNA molecule also has it. The polynucleotide chain is twisted like a spiral staircase.
The chains in the molecule are directed oppositely from each other. It turns out that if in one chain the orientation is from the 3" end to the 5", then in the other chain the orientation will be the opposite - from the 5" end to the 3".
Principle of complementarity
The two strands are joined into a molecule by nitrogenous bases in such a way that adenine has a bond with thymine, and guanine has only a bond with cytosine. Consecutive nucleotides in one chain determine the other. This correspondence, which underlies the appearance of new molecules as a result of replication or duplication, has come to be called complementarity.
It turns out that the number of adenyl nucleotides is equal to the number of thymidyl nucleotides, and guanyl nucleotides are equal to the number of cytidyl nucleotides. This correspondence became known as Chargaff's rule.
Replication
The process of self-reproduction, which occurs under the control of enzymes, is the main property of DNA.
It all starts with the unwinding of the helix thanks to the enzyme DNA polymerase. After the hydrogen bonds are broken, a daughter chain is synthesized in one and the other strand, the material for which is the free nucleotides present in the nucleus.
Each DNA strand is a template for a new strand. As a result, two absolutely identical parent molecules are obtained from one. In this case, one thread is synthesized as a continuous thread, and the other is first fragmentary, only then joining.
DNA genes
The molecule carries all the important information about nucleotides and determines the location of amino acids in proteins. The DNA of humans and all other organisms stores information about its properties, passing them on to descendants.
Part of it is a gene - a group of nucleotides that encodes information about a protein. The totality of a cell's genes forms its genotype or genome.
Genes are located on a specific section of DNA. They consist of a certain number of nucleotides that are arranged in a sequential combination. This means that the gene cannot change its place in the molecule, and it has a very specific number of nucleotides. Their sequence is unique. For example, one order is used for producing adrenaline, and another for insulin.
In addition to genes, DNA contains non-coding sequences. They regulate gene function, help chromosomes, and mark the beginning and end of a gene. But today the role of most of them remains unknown.
Ribonucleic acid
This molecule is similar in many ways to deoxyribonucleic acid. However, it is not as large as DNA. And RNA also consists of four types of polymeric nucleotides. Three of them are similar to DNA, but instead of thymine it contains uracil (U or U). In addition, RNA consists of a carbohydrate - ribose. The main difference is that the helix of this molecule is single, unlike the double helix in DNA.
Functions of RNA
The functions of ribonucleic acid are based on three different types of RNA.
Information transfers genetic information from DNA to the cytoplasm of the nucleus. It is also called matrix. This is an open chain synthesized in the nucleus using the enzyme RNA polymerase. Despite the fact that its percentage in the molecule is extremely low (from three to five percent of the cell), it has the most important function - to act as a matrix for the synthesis of proteins, informing about their structure from DNA molecules. One protein is encoded by one specific DNA, so their numerical value is equal.
The ribosomal system mainly consists of cytoplasmic granules - ribosomes. R-RNAs are synthesized in the nucleus. They account for approximately eighty percent of the entire cell. This species has a complex structure, forming loops on complementary parts, which leads to molecular self-organization into a complex body. Among them, there are three types in prokaryotes, and four in eukaryotes.
The transport acts as an “adapter”, arranging the amino acids of the polypeptide chain in the appropriate order. On average, it consists of eighty nucleotides. The cell contains, as a rule, almost fifteen percent. It is designed to transport amino acids to where protein is synthesized. There are from twenty to sixty types of transfer RNA in a cell. They all have a similar organization in space. They acquire a structure called a cloverleaf.
Meaning of RNA and DNA
When DNA was discovered, its role was not so obvious. Even today, although much more information has been revealed, some questions remain unanswered. And some may not even be formulated yet.
The well-known biological significance of DNA and RNA is that DNA transmits hereditary information, and RNA is involved in protein synthesis and encodes protein structure.
However, there are versions that this molecule is connected with our spiritual life. What is human DNA in this sense? It contains all the information about him, his life activity and heredity. Metaphysicians believe that the experience of past lives, the restoration functions of DNA, and even the energy of the Higher Self - the Creator, God, is contained in it.
In their opinion, the chains contain codes relating to all aspects of life, including the spiritual part. But some information, for example about restoring one's body, is located in the structure of the crystal of multidimensional space located around DNA. It represents a dodecahedron and is the memory of all life force.
Due to the fact that a person does not burden himself with spiritual knowledge, the exchange of information in DNA with the crystalline shell occurs very slowly. For the average person it is only fifteen percent.
It is assumed that this was done specifically to shorten human life and fall to the level of duality. Thus, a person’s karmic debt increases, and the level of vibration necessary for some entities is maintained on the planet.
The molecule is an equally important component of any organism; it is present in prokaryotic cells, and in some cells (RNA-containing viruses).
We examined the general structure and composition of the molecule in the lecture ““, here we will consider the following questions:
- RNA formation and complementarity
- transcription
- broadcast (synthesis)
RNA molecules are smaller than DNA molecules. The molecular weight of tRNA is 20-30 thousand c.u., rRNA is up to 1.5 million c.u.
RNA structure
So, the structure of the RNA molecule is a single-stranded molecule and contains 4 types of nitrogenous bases:
A, U, C And G
Nucleotides in RNA are connected into a polynucleotide chain due to the interaction of the pentose sugar of one nucleotide and the phosphoric acid residue of another.
There are 3 type of RNA:
Transcription and Broadcast
RNA transcription
So, as we know, every organism is unique.
Transcription- the process of RNA synthesis using DNA as a template, occurring in all living cells. In other words, it is the transfer of genetic information from DNA to RNA.
Accordingly, the RNA of each organism is also unique. The resulting m- (template, or information) RNA is complementary to one strand of DNA. As with DNA, it “helps” transcription RNA polymerase enzyme. Just like in , the process begins with initiation(=beginning), then goes prolongation(=extension, continuation) and ends termination(=break, ending).
At the end of the process, m-RNA is released into the cytoplasm.
Broadcast
In general, translation is a very complex process and is similar to a well-developed automatic surgical operation. We will look at a “simplified version” - just to understand the basic processes of this mechanism, the main purpose of which is to provide the body with protein.
- the m-RNA molecule leaves the nucleus into the cytoplasm and connects with the ribosome.
- At this moment, the amino acids of the cytoplasm are activated, but there is one “but” - m-RNA and amino acids cannot interact directly. They need an "adapter"
- This adapter becomes t-(transfer) RNA. Each amino acid has its own tRNA. tRNA has a special triplet of nucleotides (anticodon), which is complementary to a certain section of m-RNA, and it “attaches” an amino acid to this specific section.
- , in turn, with the help of special enzymes, forms a connection between these - the ribosome moves along the m-RNA like a slider along a snake fastener. The polypeptide chain grows until the ribosome reaches the codon (3 amino acids) that corresponds to the “STOP” signal. Then the chain breaks and the protein leaves the ribosome.
Genetic code
Genetic code- a method characteristic of all living organisms of encoding the amino acid sequence of proteins using a sequence of nucleotides.
How to use the table:
- Find the first nitrogenous base in the left column;
- Find the second base from the top;
- Determine the third base in the right column.
The intersection of all three is the amino acid of the resulting protein you need.
Properties of the genetic code
- Triplety- a meaningful unit of code is a combination of three nucleotides (triplet, or codon).
- Continuity- there are no punctuation marks between triplets, that is, the information is read continuously.
- Non-overlapping- the same nucleotide cannot simultaneously be part of two or more triplets.
- Uniqueness (specificity)- a specific codon corresponds to only one amino acid.
- Degeneracy (redundancy)- several codons can correspond to the same amino acid.
- Versatility- the genetic code works the same in organisms of different levels of complexity - from viruses to humans
There is no need to memorize these properties. It is important to understand that the genetic code is universal for all living organisms! Why? Yes because it is based on
Molecular biology is one of the most important branches of biological sciences and involves a detailed study of the cells of living organisms and their components. The scope of her research includes many vital processes such as birth, breathing, growth, death.
An invaluable discovery of molecular biology was the deciphering of the genetic code of higher beings and the determination of the cell’s ability to store and transmit genetic information. The main role in these processes belongs to nucleic acids, of which in nature there are two types - DNA and RNA. What are these macromolecules? What are they made of and what biological functions do they perform?
What is DNA?
DNA stands for deoxyribonucleic acid. It is one of the three macromolecules of the cell (the other two are proteins and ribonucleic acid), which ensures the preservation and transmission of the genetic code for the development and activity of organisms. In simple words, DNA is the carrier of genetic information. It contains the genotype of an individual, which has the ability to reproduce itself and transmits information by inheritance.
As a chemical substance, acid was isolated from cells back in the 1860s, but until the middle of the 20th century, no one imagined that it was capable of storing and transmitting information. 
For a long time it was believed that these functions were performed by proteins, but in 1953 a group of biologists was able to significantly expand the understanding of the essence of the molecule and prove the primary role of DNA in the preservation and transmission of the genotype. The discovery became the discovery of the century, and scientists received the Nobel Prize for their work.
What does DNA consist of?
DNA is the largest of biological molecules and consists of four nucleotides consisting of a phosphoric acid residue. Structurally, the acid is quite complex. Its nucleotides are connected to each other by long chains, which are combined in pairs into secondary structures - double helices.
DNA tends to be damaged by radiation or various oxidizing substances, due to which a mutation process occurs in the molecule. The functioning of the acid directly depends on its interaction with another molecule - proteins. By interacting with them in the cell, it forms the substance chromatin, within which information is realized.
What is RNA?
RNA is a ribonucleic acid containing nitrogenous bases and phosphoric acid residues. 
There is a hypothesis that it is the first molecule that acquired the ability to reproduce itself back in the era of the formation of our planet - in pre-biological systems. RNA is still included in the genomes of individual viruses today, fulfilling the role in them that DNA plays in higher beings.
Ribonucleic acid consists of 4 nucleotides, but instead of a double helix, as in DNA, its chains are connected by a single curve. Nucleotides contain ribose, which is actively involved in metabolism. Depending on their ability to encode protein, RNA is divided into template and non-coding.
The first acts as a kind of intermediary in the transfer of encoded information to ribosomes. The latter cannot encode proteins, but have other capabilities - translation and ligation of molecules.
How is DNA different from RNA?
In their chemical composition, acids are very similar to each other. Both are linear polymers and are N-glycosides created from five-carbon sugar residues. The difference between them is that the sugar residue of RNA is ribose, a monosaccharide from the pentose group, easily soluble in water. The sugar residue in DNA is deoxyribose, or a derivative of ribose, which has a slightly different structure. 
Unlike ribose, which forms a ring of 4 carbon atoms and 1 oxygen atom, in deoxyribose the second carbon atom is replaced by hydrogen. Another difference between DNA and RNA is their size - larger. In addition, among the four nucleotides included in DNA, one is a nitrogenous base called thymine, while in RNA, instead of thymine, there is a version of it - uracil.
