Solving tasks in general biology. Synthesis protein in a cage. Matrix reactions

In 1869, the Swiss biochemist Johann Friedrich Misher first discovered, allocated the cells from the cores and described DNA. But only in 1944 O. Avery, S. Makleod and M. Makarti, the genetic role of DNA was proved, that is, it was reliably established that the transfer of hereditary information is associated with deoxyribonucleic acid. This discovery was a powerful factor stimulating the study of heredity at the molecular level. Since then, the rapid development of molecular biology and genetics began.

Nucleic acids (from lat. Nucleus. - kernel) - these are natural high molecular weight organic compounds that provide storage and transmission of hereditary (genetic) information in living organisms. Their composition includes: carbon (C), hydrogen (H), oxygen (o), phosphorus (P). Nucleic acids are irregular biopolymers consisting of monomers - nucleotides. The composition of each nucleotide includes:

· nitrogenous base

· Simple carbon - 5 carbon pentosose sugar (ribose or deoxyribosis),

· The residue of phosphoric acid.

There are two types of nucleic acids: deoxyribonucleic acid - DNA containing deoxyribose, and ribonucleic acid - RNA containing ribose.

Consider each type of nucleic acids.

DNA is contained almost exclusively in the core of the cell, sometimes in organoids: mitochondria, plaststs. DNA is a polymeric compound with a constant (stable) content in the cell.

DNA structure. By its structure, the DNA molecule is two polymer chains interconnected and twisted in the form of a double helix (Fig. 1).

A model of the DNA structure in 1953 was created by D. Watson and F. Scream, for which both were awarded the Nobel Prize. The width of the double helix is \u200b\u200bonly about 0.002 μm (20 angstroms), but the length of it is exceptionally large - up to several tens and even hundreds of micrometers (for comparison: the length of the largest protein molecule in the unfolded form does not exceed 0.1 μm).

Nucleotides are located apart from each other - 0,34 NM, and one round of the spiral accounts for 10 nucleotides. The molecular weight of DNA is large: it is dozens, and even hundreds of millions. For example, molecular weight (M. R) The largest chromosome of drosophila is 7.9 10 10.

The main structural unit of one chain is a nucleotide consisting of a nitrogen base, deoxyribose and phosphate group. DNA contains 4 types of nitrogen bases:

· Purine - adenine (a) and guanine (g),

· Pyrimidine - cytosin (C) and Timin (T).

The total amount of purine bases is equal to the amount of pyrimidine.

DNA nucleotides will also be 4 species, respectively: adenyl (a), guanilla (g), cytidyl (C) and thimidyl (T), all DNA nucleotides are connected to a polynucleotide chain due to the residues of phosphoric acids located between deoxyribosis. In the polynucleotide chain there may be up to 300,000 or more nucleotides.

Thus, each DNA circuit represents a polynucleotide, in which nucleotides are located in a strictly defined order. Nitrogenous bases are suitable for each other so closely that hydrogen bonds arise between them. An important pattern is clearly manifested in their location: adenine (a) of one chain is associated with a thimine (T) of another chain by two hydrogen bonds, and the guanine (d) of one chain is associated with three hydrogen bonds with cytosign (C) another chain, resulting in a pair of AA and Mr. This ability to selectively compound nucleotides is called complementaryness, i.e., spatial and chemical correspondence between nucleotide pairs (see Fig. 2).

The sequence of connection of the nucleotide of one circuit is the opposite (complementary) to the other, that is, the chains constituting one DNA molecule, multidirectional, or anti-parallel. Chains are twisted around each other and form a double helix. A large number of hydrogen bonds provides a strong connection of DNA threads and gives a molecule stability, while maintaining its molecule - under the influence of enzymes, it is easily unwound (despirate).

DNA replication (DNA Reduction) - The process of self-reproduction (self-removal) of nucleic acid macromolecules, which ensures accurate copying of genetic information and transmitting it from generation to generation.

DNA replication occurs during the interphase period before cell division. The Maternal DNA molecule (the number of DNA chains in the cell is 2N) under the action of enzymes is unwound from one end, and then from free nucleotides on the principle of complementarity on both chains, child polynucleotide chains are completed. As a result of matrix reactions, two DNA daughter molecules in which one of the chains is old maternal, and the other - new, again synthesized (the amount of DNA in the cell becomes 4N \u003d 2 x 2N).

DNA functions.

1. Storage of hereditary information on the structure of proteins or its individual organoids. The smallest unit of genetic information after nucleotide is three consecutive nucleotides - a triplet. The sequence of triplets in the polynucleotide chain defines the sequence of amino acids of one protein molecule (primary protein structure) and is a gene. Together with DNA proteins, it is part of chromatin, a substance from which the chromosome of the cell core.

2. The transfer of hereditary information as a result of replications for cellular division from the mother cell is a subsidiary.

3. The implementation of hereditary information (stored in the form of genes) as a result of matrix biosynthesis reactions through the production of specific cells and the organism of proteins. At the same time, on one of its chains on the principle of complementarity from nucleotides of the surrounding molecule of the medium, the information RNA molecules are synthesized.

RNA - connection with oscillating (labile) content in the cell.

RNA structure. By its structure, the RNA molecule is less large than DNA molecules with a molecular weight of 20-30 thousand (TRNA) to 1 million (RRNA), RNA is a single-chain molecule, built in the same way as one of the DNA chains. RNA monomers - nucleotides consist of a nitrogen base, ribose (pentoses) and phosphate group. RNA contains 4 nitrogen bases:

· Purine - adenine (a);

· Pyrimidine - Guanine (g), cytosine (C), Uracil (y).

In RNA, the Timin is replaced by the Uracil close to it on the structure (nucleotide - uridyl. The nucleotides are connected to the polynucleotide chain in the same way as in DNA, due to the residues of phosphoric acids located between ribosis.

At the location of the cell Among RNA is distinguished: nuclear, cytoplasmic, mitochondrial, plastic.

According to the functions performed Among RNA are distinguished: transport, information and ribosomal.

Transport RNA (TRNA) - single-chain, but having a three-dimensional structure "clover leaf" created by intramolecular hydrogen bonds (Fig. 3). TRNA molecules are the shortest. Consist of 80-100 nucleotides. They account for about 10% of the total RNA content in the cell. They transfer activated amino acids (each TRNA of its amino acid is all known 61 TRNA) to ribosomes with protein biosynthesis in the cell. "

Information (matrix) RNA (IRNA, MRNA) - single-stranded molecule, which is formed as a result of transcription on the DNA molecule (copies the genes) in the kernel and carries information about the primary structure of one protein molecule to the site of protein synthesis in ribosomes. The IRNN molecule may consist of 300-3000 nucleotides. The share of IRNA accounts for 0.5-1% of the total RNA content in the cell.

Ribosomal RNA (RRNA) - The largest single-stranded molecules that form together with proteins complex complexes that support the structure of the ribosomes on which protein synthesis is.

The share of RRNA accounts for about 90% of the total RNA content in the cell.

All genetic information of the organism (the structure of its proteins) is enclosed in its DNA consisting of nucleotides combined into genes. Recall that the gene is a unit of hereditary information (section of the DNA molecule), containing information about the structure of one protein - enzyme. Genes caused by the properties of organisms call structural.And genes that regulate the manifestation of structural genes are called regulatory.The manifestation (expression) of the gene (the implementation of hereditary information) occurs as follows:

For the implementation of the gene expression, there is a genetic code - strictly ordered dependence between the bases of nucleotides and amino acids (Table 12).

Table 12. Genetic code

The main properties of the genetic code.

Triplet - Coding of amino acids is carried out by three (trips) of nucleotide bases. The number of coding triplets is 64 (4 types of nucleotides: A, T, C, G, 4 3 \u003d 64).

Unrecognition - Each triplet encodes only one amino acid.

Departure - The number of coding triplets exceeds the number of amino acids (64\u003e 20). There are amino acids encoded by more than one triplet (in the composition of proteins such amino acids occur more often). There are three triplets that do not coding any amino acid (UAA, UAG, UGA). They are called "nonsense codons" and play the role of "stop signals", meaning the end of the gene recording (the total number of encoder codons - 61).

Implementability (continuity) - Reading triplets with DNA in the synthesis of IRNK goes strictly in three consecutive nucleotides, without overlapping adjacent codons. Inside the gene no "punctuation marks".

Universality - Some and the same thrips encode the same amino acids in all organisms living on Earth.

Generally accepted reduction in the names of amino acids:

Feng - phenylalanine; GIS - Gistidin;

Lei - Leucin; GLN - glutamine;

Ile - isoleucine; Depth - glutamic acid;

Met - methionine; Liz - lysine;

Shaft - Valin; ASN - Asparagin;

Ser - series; ASP - asparagic acid;

Pro - proline; Cis - cysteine;

Treonin; Three - tryptophan;

Ala - Alanine; Arg - Arginine;

Tir - Tyrosine; Gly - Glycine.

Thus, the DNA carrier of all genetic information in the cell is directly involved in the synthesis of protein (i.e., the implementation of this hereditary information) is not accepted. In animal cells and plants, DNA molecules are separated by a nuclear membrane from cytoplasma where protein synthesis occurs. To ribosomes - places of protein assembly - sent from the core an intermediary who carries copied information and is able to go through the pores of the nuclear membrane. Such an intermediary is an information RNA, which is involved in matrix reactions.

Matrix reactions - This is the reaction of the synthesis of new compounds based on the "old" macromolecules performing the role of the matrix, i.e., forms, sample for copying new molecules. Matrix reactions to the implementation of hereditary information in which DNA and RNA participate are:

1. DNA replication - Doubling DNA molecules, thanks to which the transfer of genetic information is carried out from generation to generation. The matrix is \u200b\u200bthe maternal DNA, and new, formed on this matrix - child, newly synthesized 2 DNA molecules (Fig. 4).

2. Transcription (LAT. Transcription - rewriting) is the synthesis of RNA molecules on the principle of complementarity on the matrix of one of the DNA chains. It occurs in the kernel under the action of the enzyme DNA-dependent - RNA polymerase. Information RNA is onenonite molecule, and gene encoding comes with one yarn two-way DNA molecule. If a nucleotide r nucleotide is under transcribed DNA threads, then the DNA polymerase comprises C to the composition of the IRNA, if it is worth t, then it turns on the IRNA, if it is worth t, it turns on (in the composition of RNA, Timin T; Fig. 5). The Language of DNA triplets is translated into the IRNN Code Code (Triplets in IRNA are called codons).

As a result of the transcription of different genes, all types of RNA are synthesized. Then the IRNK, TRNA, PPHK through the pores in the nuclear shell overlook the cell cytoplasm to perform their functions.

3. Translation (Lat. Translatio - Transmission, translation) is the synthesis of polypeptide protein chains on a matrix of mature IRNK, carried out by ribosomes. In this process, several stages are distinguished:

Stage first - initiation (start of synthesis - chains). In the cytoplasm to one of the ends of the IRNK (exactly the one with which the synthesis of the molecule in the kernel began) enters the ribosome and starts the synthesis of the polypeptide. Molecule TRNA, transporting the amino acid of methionine (TRNA Met), is connected to the ribosome and is attached to the beginning of the IRNA chain (always by the AUG code). Next to the first TRNA (having no relation to the synthesizing protein) joins the second TRNA with amino acid. If anti-cymodone TRNA, then between the amino acids there is a peptide bond, which forms a certain enzyme. After that, TRNA leaves Ribosomes (goes to the cytoplasm for a new amino acid), and the IRNK is moving to one codon.

The second stage is the elongation (chain elongation). Ribosome moves along the INNK molecule not smoothly, but intermittently, triplet for the triplet. The third TRNA with the amino acid is associated with its anti-Kodon with the Code of IRNK. When establishing the Communication Communication of the Ribosoma, it takes another step to one "codon", and the specific enzyme "sews" the second and third amino acid - a peptide chain is formed. The amino acids in the growing polypeptide chain are connected in the sequence in which their codons encrypters are located (Fig. 6).

Third stage - termination (end of synthesis) chains. It occurs when broadcasting the ribosome of one of the three "nonsense-codons" (UAA, UAG, UGA). Ribosomes score with IRNA, protein synthesis completed.

Thus, knowing the order of amino acids in the protein molecule, it is possible to determine the procedure for nucleotides (triplets) in the IRNK chain, and according to it, the order of nucleotide pairs in the DNA section and vice versa, given the principle of nucleotide complementarity.

Naturally, in the process of matrix reactions due to any causes (natural or artificial), changes can occur - mutations. These are gene mutations at the molecular level - the result of various damage in DNA molecules. Gene mutations occurring at the molecular level affect, as a rule, one or more nucleotides. All forms of gene mutations can be divided into two large groups.

First group - shift of the reading frame - represents inserts or loss of one or more nucleotides pairs. Depending on the disorder, this is changed by this or that quantos. These are the most severe damage to genes, since completely different amino acids will be included in the protein.

There are 80% of all spontaneous gene mutations on such deletions and inserts.

The most damaging effects have so-called nonsense mutations, which are associated with the advent of codon terminators causingku synthesis protein. This can lead to a premature end of the synthesis of protein, which is rapidly degrading. The result is the cell death or the change in the nature of individual development.

Mutations associated with replacing, falling out or insert in the encoding part of the gene phenotypically manifest as a replacement of amino acids in protein. Depending on the nature of the amino acids and the functional significance of the disturbed area, a complete or partial loss of protein functional activity is observed. As a rule, this is expressed in reducing the viability, change in the signs of organisms, etc.

Second group - These are gene mutations with the replacement of nucleotide base pairs. There are two types of replacing grounds:

1. Transition - replacement of one purine on a purine base (and on g or g at a) or one pyrimidine on pyrimidine (C per T or T on, C).

2. Transverse - replacement of one purine base on pyrimidine or vice versa (and on C, or r at T, or on y).

A bright example of transverse is a sickle cell anemia that arises due to hereditary violation of the hemoglobin structure. The mutant gene encoding one of the chains of hemoglobin is disturbed only one nucleotide, and Adenin's replacement is replaced by Uracil (GAA to Guo).

As a result, a change in the biochemical phenotype occurs, in the hemoglobin chain, glutamy acid is replaced with valine. This replacement changes the surface of the hemoglobin molecule: instead of a biconed disk, the erythrocyte cells become similar to sickles and either block small vessels, or quickly removed from blood circulation, which quickly leads to anemia.

Thus, the significance of gene mutations for the livelihoods of the body is not the same:

· Some "silent mutations" do not affect the structure and function of the protein (for example, the replacement of the nucleotide, which does not lead to the replacement of amino acids);

· Some mutations lead to the complete loss of the protein function and cell death (for example, nonsense mutations);

· Other mutations - with a qualitative change in IRNA and amino acids lead to a change in the signs of the body;

· And finally, some mutations that change the properties of protein molecules have a damaging effect on the vital activity of cells - such mutations determine the difficult course of the disease (for example, transversions).

With the reactions of matrix synthesis, polymers are formed, the structure of which is fully determined by the structure of the matrix. The reaction of matrix synthesis is based on complementary interaction between nucleotides.

Replication (Reducing, DNA Doubling).

Matrix - Maternal DNA Chain
Product - Synthesized Chain of DNA DNA
Complementarity between nucleotides of the maternal and subsidiary chains of DNA.

A double DNA spiral is unwinded into two single, then the DNA polymerase enzyme completes each single chain to double on the principle of complementarity.

Transcription (RNA synthesis).

Matrix - Coding DNA Chain
Product - RNA
Complementarity between the nucleotides of cDNA and RNA.

In a certain section of DNA, hydrogen bonds are breaking, two single chains are obtained. At one of them, IRNK is built on the principle of complementarity. It is then disconnected and goes into the cytoplasm, and the DNA chains are again connected to each other.

Broadcast (protein synthesis).

Matrix - IRNK.
Product - Belok.
The complementarity between the nucleotides of codons of IRNK and nucleotides of anti-cymodow TRNA, bringing amino acids.

Inside the ribosomes, anticodones TRNA are joined in the codons of the IRNNC on the principle of complementarity. The ribosoma connects the amino acids brought by TRNA, the protein is obtained.

Stages of protein biosynthesis in prokaryotm and eukaryotes.

Prokaryotis protein synthesis is carried out in 2 stages:

1) transcription, product of this reaction - mRNA;

2) Broadcast, the product of this reaction is a polypeptide.

These stages can proceed simultaneously because there is no nuclear shell in the cage.

The protein synthesis process in eukaryotes includes 3 stages:

1) transcriptionDNA in pro-mRNA (product: pro-mRNA);

2) processing -transformation of pro-mRNA into mature mRNA;

3) broadcastmRNA in the polypeptide.

In some cases, it is necessary to obtain an active protein to obtain its chemical transformation, which is called posttranslation modification.

The concept of transcripton. The features of the structure of the transcripton in prokaryotm and eukaryotes.

Gene together with auxiliary sites is called transcriptonTherefore, the transcripton is the smallest functional unit of the genome.

Typical transcripton contains: promoter - signal of the start of transcription, to which the RNA polymerase enzyme is joined; terminator - signal termination signal; Regulatory plot - operator, to which the control proteins are joined by activators or repressors (they make it easier and block the transcription); structural Gen..

The structure of the transcripton prokaryotes.The prokaryotes in the transcriptone includes two sections: regulatoryand structural. These areas are 10% and 90% respectively. The regulatory portion contains a promoter, an operator and a terminator. The structural portion can be represented by one or several structural genes. In the latter case, they are divided by obscene areas - spacers. This transcripton is called operon.

W. eukarot.transcripton also contains regulatoryand structural Plots, the relative proportion of which, as opposed to prokaryotam, is 90% and 10%. The regulatory portion includes several promoters, operators and terminators. Structural genes may be in different parts of one chromosome or even in different chromosomes. The structural section of the transcripton has intermittent(mosaic) structure: sections that carry information on the sequence of amino acids in protein (coding or exonsions) Alternate with the unexploding fragments ( intron). The number of introns in various organisms is different, but, as a rule, the total length of the intron exceeds the total length of exon.

Transcription mechanisms.

Transcription- This is the process of copying the DNA section in the form of the pro-MRNA complementary to it (the predecessor of mRNA), occurs in the cell core. It begins with the attachment of the RNA polymerase enzyme to the promoter. DNA on a certain area is unchecked, the hydrogen bonds are ruined between 2 of the nucleotide chains, as a result, 2 separate polynucleotide chains are formed. To them, free nucleotides are joined on the principle of complementaryness from the carolymph. The enzyme continues to attach nucleotides until it reaches the terminator codon. Upon completion of the DNA transcription, the initial two-chain structure is restored, pro-mRNA is transported to the cytoplasm.

1. Explain the sequence of genetic information: gene - protein - a sign.

2. Remember what protein structure defines its structure and properties. How is this structure encoded in a DNA molecule?

3. What is a genetic code?

4. Describe the properties of the genetic code.

7. Reactions of matrix synthesis. Transcription

Information about the protein is recorded as a nucleotide sequence in DNA and is in the kernel. Actually protein synthesis occurs in the cytoplasm on ribosomes. Therefore, the protein synthesis requires a structure that would transfer information from DNA to the site of protein synthesis. Such an intermediary is information, or matrix, RNA, which transmits information from a certain DNA molecule gene to the site of protein synthesis on ribosomes.

In addition to the carrier of information, substances are needed that would ensure the delivery of amino acids to the synthesis site and the definition of their place in the polypeptide chain. Such substances are transport RNAs that provide encoding and delivering amino acids to the synthesis site. The protein synthesis flows on ribosomes whose body is built from ribosomal RNA. So, another type of RNA is needed - ribosomal.

Genetic information is implemented in three types of reactions: RNA synthesis, protein synthesis, DNA replication. In each of them, the information concluded in the linear sequence of nucleotides is used to create another linear sequence: either nucleotides (in RNA or DNA molecules), or amino acids (in protein molecules). It was experimentally proved that it was the DNA that serves as a matrix for the synthesis of all nucleic acids. These biosynthesis reactions are called matrix synthesis. Sufficient simplicity of matrix reactions and their one-dimensionalness allowed to study in detail and understand their mechanism, in contrast to other processes occurring in the cell.

Transcription

The process of RNA biosynthesis on DNA is called transcription. This process flows into the kernel. On the DNA matrix, all types of RNA are synthesized - information, transport and ribosomal, which are subsequently involved in protein synthesis. Genetic code for DNA in the transcription process is rewritten to information RNA. The reaction is based on the principle of complementarity.

RNA synthesis has a number of features. RNA molecule is significantly shorter and is a copy of only a small section of DNA. Therefore, the matrix serves only a certain part of DNA, where information about this nucleic acid is located. The newly synthesized RNA never remains associated with the original DNA matrix, and is released after the end of the reaction. The transcription process takes place in three stages.

First stage - initiation - The beginning of the process. Synthesis RNA copies begins with a specific DNA zone, which is called promoter. This zone contains a specific set of nucleotides that are start signals. The process is catalyzed by enzymes RNA polymerase. The RNA-polymerase enzyme is connected to the promoter, spinning the double helix and destroys the hydrogen bonds between the two DNA chains. But only one of them serves as a matrix for RNA synthesis.

Second phase - elongation. This stage takes place the main process. On the same DNA circuit, as on the matrix, nucleotides are built on the principle of complementarity (Fig. 19). The RNA-polymerase enzyme, moved step by step along the DNA chain, connects the nucleotides among themselves, at the same time constantly spinning further DNA helix. As a result of such a movement, a RNA copy is synthesized.

Third stage - termination. This is the final stage. RNA synthesis continues to stop signal - a certain sequence of nucleotides, which stops the movement of the enzyme and synthesis of RNA. Polymerase is separated from DNA and a synthesized RNA copy. Simultaneously with the matrix, the RNA molecule is removed. DNA restores a double helix. Synthesis completed. Depending on the DNA section, ribosomal, transport, information RNA is synthesized in this way.

The matrix for transcription of the RNA molecule is only one of the DNA chains. However, the matrix of two neighboring genes can serve different DNA chains. Which of the two chains will be used for the synthesis, is determined by the promoter, which sends the RNA polymerase enzyme in one direction or another direction.

After the transcription of the molecule of the information RNA of eukaryotic cells is subjected to restructuring. It is cut into nucleotide sequences that do not carry information about this protein. This process is called splicing. Depending on the type of cell and the development stage, different parts of the RNA molecule can be removed. Consequently, different RNAs are synthesized in one section of DNA, which carry information about various proteins. This ensures the transfer of significant genetic information from one gene, and also facilitates genetic recombination.

Fig. 19. Synthesis of information RNA. 1 - DNA chain; 2 - Synthesized RNA

Questions and tasks for self-control

1. What reactions relate to the reactions of matrix synthesis?

2. What is the initial matrix for all reactions of matrix synthesis?

3. What is the name of the IRNK biosynthesis process?

4. What types of RNA are synthesized on DNA?

5. Install the IRNN fragment sequence if the appropriate fragment on DNA has a sequence: AAGTSTCTGATTSTGATTSGATSTAATIGA.

8. Biosynthesis protein

Proteins are the necessary components of all cells, therefore the most important process of plastic exchange is protein biosynthesis. It proceeds in all cells of organisms. These are the only components of the cell (except nucleic acids), the synthesis of which is carried out under the direct control of the genetic material of the cell. The entire genetic apparatus of cells - DNA and different types of RNA are configured to protein synthesis.

Gene - This is a portion of a DNA molecule, responsible for the synthesis of one protein molecule. For protein synthesis, it is necessary that a certain gene with DNA be copied as an information RNA molecule. This process was reviewed earlier. The protein synthesis is a complex multi-step process and depends on the activities of various types of RNA. For direct protein biosynthesis, the following components are needed:

1. Information RNA - a carrier of information from DNA to the place of synthesis. IRNN molecules are synthesized during transcription.

2. Ribosomes - organides, where protein synthesis occurs.

3. A set of necessary amino acids in the cytoplasm.

4. Transport RNA encoding amino acids and carry them to the place of synthesis on ribosomes.

5. ATP is a substance that provides the energy of the encoding of amino acids and the synthesis of the polypeptide chain.

The structure of transport RNA and encoding amino acids

Transport RNA (TRNA) are small molecules with the number of nucleotides from 70 to 90. The share of TRNA accounts for about 15% of all cell RNA. The TRNA function depends on its structure. Studying the structure of TRNA molecules showed that they are minimized in a certain way and have the kind clover sheet (Fig. 20). The molecule is distinguished by loops and double sections, connected by interaction between complementary bases. The most important is the central loop in which antikodon - The nucleotide triplet corresponding to the code of a certain amino acid. With its anti-cymodone TRNA, it is capable of connecting to the corresponding codon on the IRNA on the principle of complementarity.

Fig. 20. The structure of the TRNA molecule: 1 - anticodone; 2 - Amino Acid Attachment Place

Each TRNA can carry only one of 20 amino acids. So, for each amino acid there is at least one TRNA. Since the amino acid can have several triplets, then the number of types of TRNA is equal to the number of amino acid triplets. Thus, the total number of types of TRNA corresponds to the number of codons and is equal to 61. Neither TRNA does not correspond to the three stop codes.

At one end, the TRNA molecule is always located a nucleotide Guanine (5 "-Conal), and on the other (3" -concar) always three Nucleotides of the CCA. It is to this end that the amino acid is connected (Fig. 21). Each amino acid joins its specific TRNA with the corresponding anti-Kodonon. The mechanism of this accession is associated with the work of specific enzymes - aminoacil-TNA synthetases, which attach each amino acid to the corresponding TRNA. For each amino acid there is its own synthetia. The compound of amino acids with TRNA is carried out due to the energy of ATP, while the macro-ergic bond goes into relationship between TRNA and amino acid. This is how the amino acids are activated and encoding.

Stages of protein biosynthesis. The process of synthesis of the polypeptide chain carried out on the ribosome is called broadcast. Information RNA (IRNK) is an intermediary in the transfer of information on the primary protein structure, TRNA transfers the encoded amino acids to the synthesis site and ensures the sequence of their compounds. In ribosomes, a polypeptide chain is assembling.

What reactions occurring in the cell include the reactions of matrix synthesis? What does the matrices of such reactions?

Matrix synthesis is a specific feature of living organisms. The matrix is \u200b\u200ba sample by which a copy is formed. Matrix synthesis - synthesis in the matrix. Due to the reactions of matrix synthesis, an accurate sequence of monomers for the creation of polymers is ensured.

The reactions of the matrix synthesis occurring in the cell include DNA doubling reactions, RNA synthesis, protein synthesis. The matrix is \u200b\u200bDNA in the synthesis of IRNA and DNA or RNA in protein synthesis. Matrix synthesis monomers are nucleotides and amino acids. The monomers are fixed on the matrix on the principle of complementarity, stitch and then reset from the matrix. The reactions of matrix synthesis are the basis for reproducing themselves like.

What reactions occurring in the cell include the reactions of matrix synthesis? What does the matrices of such reactions?

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• monomers of reactions of matrix synthesis in the cell serve
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1. DVOTION DNA

2. Synthesis RRNA.

3. Synthesis of glucose starch

4. Synthesis protein in ribosomes

3. Genotype is

1. Set of genes in genital chromosomes

2. A set of genes in one chromosome

3. Set of genes in the diploid set of chromosomes

4. Set of genes in the X chromosome

4. A man for hemophilia corresponds to a recessive allele, adopted with the floor. When married women - carrier allele hemophilia and a healthy man

1. The likelihood of the birth of patients with hemophilia boys and girls - 50%

2. 50% of boys will be sick, and all girls are carrier

3. 50% of boys will be sick, and 50% of girls - carrier

4. 50% of girls will be sick, and all boys are carriers

5. Inheritance, adhesive with floor - is the inheritance of signs that always

1. Manifested only in male individuals

2. Manifest only in hawk organisms

3. Determined by genes in sex chromosomes

4. are secondary sexual features

In man

1. 23 clutch groups

2. 46 clutch groups

3. One clutch group

4. 92 clutch groups

Carriers of Dalton's gene whose disease does not appear may be

1. Only women

2. Only men

3. And women, and men

4. Only women with a set of genital chromosomes ho

In the nucleus of man

1. Low chord, abdominal nervous chain and gill arcs

2. Low chord, gill arches and tail

3. Low chord and abdominal nervous chain

4. The abdominal nervous chain and tail is laid

The fetus of a person oxygen enters the blood through

1. Label slut

4. Undermined rope

The twin research method is carried out by

1. Crossing

2. Research of pedigree

3. Observations for objects of research

4. Artificial Mutagesis

8) Basics of Immunology

1. Antibodies are

1. Phagocyte cells

2. Belkov molecules

3. Lymphocytes

4. Cells of microorganisms infecting man

With a risk of infection with a tetanus (for example, with the pollution of the RAS, the soil is administered to a person with anticipatural serum. It contains

1. Proteins antibodies

2. Relative bacteria-tetanus bacterities

3. Antibiotics

4. Antigen bacteria tetanus

Mother's milk ensures child immunity thanks

1. Macroelements

2. Laminating acid bacteria

3. Microelements

4. Antibodies

In lymphatic capillaries

1. Lymph of lymphatic ducts

2. Blood from the arteries

3. Blood from veins

4. Intercellular liquid from tissues

Phagocyte cells are present in humans

1. In most tissues and body bodies

2. Only in lymphatic vessels and nodes

3. Only in blood vessels

4. Only in the circulatory and lymphatic system

6. With what their listed processes in the human body synthesizes ATP?

1. Split proteins on amino acids

2. Glycogen cleavage to glucose

3. Fat cleavage for glycerin and fatty acids

4. Hexless glucose oxidation (Glycoliz)

7. For its physiological role, most vitamins are

1. Enzymes

2. Activators (Cofactors) Enzymes

3. An important source of energy for the body

4. Hormones

Twilight violation and dry eye cornea can be a sign of vitamin deficiency