What reactions occurring in the cell are referred to as matrix synthesis reactions? What is the matrix of such reactions? Does not apply to matrix synthesis reactions.

1. DNA duplication

2. rRNA synthesis

3. synthesis of starch from glucose

4. protein synthesis in ribosomes

3. The genotype is

1. set of genes in sex chromosomes

2. set of genes in one chromosome

3. set of genes in a diploid set of chromosomes

4. a set of genes on the X chromosome

4. In humans, a sex-linked recessive allele is responsible for hemophilia. When a woman is a carrier of the hemophilia allele and a healthy man is married

1. The probability of the birth of boys and girls with hemophilia is 50%

2. 50% of boys will be affected and all girls will be carriers

3. 50% of boys will be sick and 50% of girls will be carriers

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

5. Sex-linked inheritance is the inheritance of traits that are always

1. appear only in males

2. appear only in sexually mature organisms

3. determined by genes located on the sex chromosomes

4. are secondary sexual characteristics

In man

1. 23 clutch groups

2. 46 clutch groups

3. one clutch group

4. 92 clutch groups

Carriers of the gene for color blindness, in whom the disease does not manifest itself, may be

1. women only

2. men only

3. both women and men

4. only women with a set of XO sex chromosomes

In the human fetus

1. chord, abdominal nerve chain and gill arches are laid

2. chord, gill arches and tail are laid

3. chord and abdominal nerve chain are laid

4. the ventral nerve chain and tail are laid

In the human fetus, oxygen enters the blood through

1. gill slits

4. umbilical cord

The twin research method is carried out by

1. crossing

2. Pedigree studies

3. observations of the objects of study

4. artificial mutagenesis

8) Fundamentals of Immunology

1. Antibodies are

1. phagocyte cells

2. protein molecules

3. lymphocytes

4. cells of microorganisms that infect humans

If there is a risk of infection with tetanus (for example, when wounds are contaminated with soil), antitetanus serum is administered to a person. It contains

1. proteins-antibodies

2. weakened tetanus bacteria

3. antibiotics

4. antigens of tetanus bacteria

Mother's milk provides immunity to the child due to

1. macronutrients

2. lactic acid bacteria

3. trace elements

4. antibodies

Enters the lymphatic capillaries

1. lymph from the lymphatic ducts

2. blood from arteries

3. blood from veins

4. intercellular fluid from tissues

Phagocyte cells are present in humans

1. in most tissues and organs of the body

2. only in lymphatic vessels and nodes

3. only in blood vessels

4. only in the circulatory and lymphatic system

6. Which of the listed processes in the human body synthesizes ATP?

1. breakdown of proteins into amino acids

2. breakdown of glycogen to glucose

3. breakdown of fats into glycerol and fatty acids

4. oxygen-free oxidation of glucose (glycolysis)

7. According to their physiological role, most vitamins are

1. enzymes

2. activators (cofactors) of enzymes

3. an important source of energy for the body

4. hormones

Violation of twilight vision and dryness of the cornea of ​​\u200b\u200bthe eyes can be a sign of vitamin deficiency.

replication

The process of DNA replication takes place in the nucleus under the action of enzymes and special protein complexes. Principles of DNA duplication:

• * anti-parallelism : the daughter strand is synthesized in the direction from 5" to 3" end.
• * Complimentary : the structure of the daughter DNA strand is determined by the nucleotide sequence of the parent strand, selected according to the principle of complementarity.
• * semi-continuity : one of the two strands of DNA leading , is synthesized continuously, and the other - delayed , intermittently with the formation of short fragments Okazaki . This is due to the anti-parallelism property.
• * semi-conservative : DNA molecules obtained during reduplication contain one conserved maternal strand and one synthesized child.
• 1) Initiation

Begin with replicative point to which the proteins that initiate replication are attached. Under the action of enzymes DNA topoisomerases And DNA helicases the chain unwinds and the hydrogen bonds are broken. Next comes the fragmentary separation of the DNA double strand with the formation replication fork . Enzymes prevent DNA strands from reconnecting.

2) Elongation

The synthesis of the daughter strand of DNA is due to the enzyme DNA polymerase , which moves in the direction 5" 3" , selecting nucleotides according to the principle of complementarity. The leading strand is synthesized continuously, and the lagging strand is intermittently synthesized. Enzyme DNA ligase interconnects fragments of Okazaki . Special corrective proteins recognize errors and eliminate incorrect nucleotides.

3) Termination

Replication ends when two replication forks meet. Protein components are removed, DNA molecules are spiralized.

Properties genetic code

• * triplet Each amino acid is encoded by a code of 3 nucleotides.
• * unambiguous - each triplet encodes only a certain acid.
• * Degenerate - each amino acid is encoded by several triplets (2-6). Only two of them are encoded by one triplet: tryptophan and methionine.
• * non-overlapping - each codon is an independent unit, and genetic inf is read only in one way in one direction
• * Universal is the same for all organisms. The same triplets code for the same amino acids in different organisms.

Genetic code

The implementation of hereditary information follows the gene-protein-trait scheme.

Gene - a section of a DNA molecule that carries information about the primary structure of one protein molecule and is responsible for its synthesis.

Genetic code - the principle of encoding hereditary inf in a cell. It is a sequence of nucleotide triplets in NA that defines certain order amino acids in proteins. Infa contained in a linear sequence of nucleotides is used to create another sequence.

4 nucleotides can make 64 triplet , 61 of which code for amino acids. Stop codons - triplets UAA, UAG, UGA stop the synthesis of the polypeptide chain.

start codon - triplet AUG determines the beginning of the synthesis of the polypeptide chain.

Protein biosynthesis

One of the main processes of plastic metabolism. Some of the reactions take place in the nucleus, the other - in the cytoplasm. Necessary components: ATP, DNA, i-RNA, t-RNA, r-RNA, Mg 2+, amino acids, enzymes. Consists of 3 processes:

• - transcription : mRNA synthesis
• - processing : mRNA to mRNA conversion
• - broadcast : protein synthesis

DNA contains information about the structure of a protein in the form of a sequence of amino acids, but since the genes do not leave the nucleus, they do not take a direct part in the biosynthesis of the protein molecule. I-RNA is synthesized in the cell nucleus by DNA and transfers inf from DNA to the site of protein synthesis (ribosomes). Then, with the help of tRNA, amino acids complementary to mRNA are selected from the cytoplasm. Thus, polypeptide chains are synthesized.

Transcription

1) Initiation

Synthesis of mRNA molecules by DNA can occur in the nucleus, mitochondria and plastids. Under the action of the enzymes DNA helicase and DNA topoisomerase, a section of the DNA molecule unwinds , hydrogen bonds are broken. Reading information comes from only one strand of DNA, which is called coding codogenic . Enzyme RNA polymerase connects with promoter - a zone of DNA that contains the start signal TATA.

2) Elongation

The process of aligning nucleotides according to the principle complimentary . RNA polymerase moves along the coding chain and joins nucleotides together, forming a polynucleotide chain. The process continues until stop codon .

3) Termination

Completion of the synthesis: the enzyme and the synthesized RNA molecule are separated from the DNA, the DNA double helix is ​​restored.

Processing

The transformation of an mRNA molecule into mRNA during splicing in the nucleus under the action of enzymes. Deletion in progress introns -areas that do not carry information about the amino acid sequence and crosslinking exons - plots encoding the sequence of amino acids. This is followed by addition of the AUG stop codon, capping for the 5' end, and polyadenylation to protect the 3' end. Mature mRNA is formed, it is shorter and goes to the ribosomes.

Broadcast

The process of translating the nucleotide sequence of mRNA triplets into the amino acid sequence of a polypeptide chain. Occurs in the cytoplasm on ribosomes.

1) Initiation

The synthesized mRNA passes through the nuclear pores to the cytoplasm, where, with the help of enzymes and the energy of ATP, it combines with small ribosome subunit. Then the initiator tRNA with the amino acid methianine binds to the peptidyl center. Further, in the presence of Mg 2+, the addition big subunits.

2) Elongation

Protein chain elongation. Amino acids are delivered to ribosomes by their own tRNA. The shape of the tRNA molecule resembles a shamrock, on the middle of which there is anticodon , complementary to mRNA codon nucleotides. The corresponding amino acid is attached to the opposite base of the tRNA molecule.

The first tRNA is anchored in peptidyl center, and the second - in aminoacial . Then the amino acids come together and form between them peptide connection, a dipeptide appears, the first t-RNA goes into the cytoplasm. After that, the ribosome makes 1 trinucleotide step by mRNA. As a result, the second t-RNA is in the peptidyl center, freeing the aminoacyl one. The process of attaching amino acids takes the energy of ATP and requires the presence of an enzyme. aminoacyl-t-RNA synthetase .

3) Termination

When a stop codon enters the aminoacid center, synthesis is completed and water is added to the last amino acid. The ribosome is removed from the mRNA and splits into 2 subunits, the tRNA returns to the cytoplasm.

Matrix synthesis is the formation of a biopolymer, the sequence of links in which is determined by the primary structure of another molecule. The latter, as it were, plays the role of a matrix that "dictates" the desired order of chain assembly. Three biosynthetic processes based on this mechanism are known in living cells.

What molecules are synthesized based on the matrix

Matrix synthesis reactions include:

• replication - doubling of genetic material;
• transcription - ribo synthesis nucleic acids;
• translation - the production of protein molecules.

Replication is the transformation of one DNA molecule into two identical to each other, which is of great importance for the life cycle of cells (mitosis, meiosis, plasmid doubling, bacterial cell division, etc.). Many processes are based on the "reproduction" of genetic material, and matrix synthesis allows you to recreate exact copy any DNA molecule.

Transcription and translation are two stages in the implementation of the genome. In this case, the hereditary information recorded in DNA is converted into a specific protein set, on which the phenotype of the organism depends. This mechanism is referred to as the DNA-RNA-protein pathway and is one of the central dogmas of molecular biology.

The implementation of this principle is achieved with the help of matrix synthesis, which matches the process of formation of a new molecule with the "original sample". The basis of such conjugation is the fundamental principle of complementarity.

Main aspects of the synthesis of molecules based on a matrix

Information about the structure of the synthesized molecule is contained in the sequence of links of the matrix itself, to each of which the corresponding element of the "daughter" chain is selected. If the chemical nature of the synthesized and template molecules are the same (DNA-DNA or DNA-RNA), then conjugation occurs directly, since each nucleotide has a pair with which it can bind.

Protein synthesis requires a mediator, one part of which interacts with the template by the nucleotide correspondence mechanism, while the other part attaches protein units. Thus, the principle of nucleotide complementarity also works in this case, although it does not directly link the links of the template and synthesized chains.

Stages of synthesis

All matrix synthesis processes are divided into three stages:

• initiation (beginning);
• elongation;
• termination (end).

Initiation is a preparation for synthesis, the nature of which depends on the type of process. The main goal of this stage is to bring the enzyme-substrate system into working condition.

During elongation, the synthesized chain is directly extended, in which a covalent bond (peptide or phosphodiester) is closed between the links selected according to the matrix sequence. Termination stops the synthesis and releases the product.

The role of complementarity in the mechanism of matrix synthesis

The principle of complementarity is based on the selective correspondence of the nitrogenous bases of nucleotides to each other. So, only thymine or uracil (double bond) is suitable as a pair for adenine, and cytosine (3 triple bond) for guanine.

In the process of nucleic acid synthesis, complementary nucleotides bind to the units of a single-stranded template, lining up in a certain sequence. Thus, based on the AACGTT DNA region, only TTGCAA can be obtained during replication, and UUGCAA during transcription.

As noted above, protein synthesis occurs with the participation of an intermediary. This role is performed by transfer RNA, which has a site for attaching an amino acid and a nucleotide triplet (anticodon) designed to bind to messenger RNA.

In this case, complementary selection occurs not by one, but by three nucleotides. Since each amino acid is specific to only one type of tRNA, and the anticodon corresponds to a specific triplet in RNA, a protein is synthesized with a specific sequence of links that is embedded in the genome.

How does replication work?

Matrix DNA synthesis occurs with the participation of many enzymes and auxiliary proteins. The key components are:

• DNA helicase - unwinds the double helix, destroys the bonds between the chains of the molecule;
• DNA ligase - "sews up" gaps between Okazaki fragments;
• primase - synthesizes the primer necessary for the operation of the DNA-synthesizing fragment;
• SSB proteins - stabilize single-stranded fragments of untwisted DNA;
• DNA polymerases - synthesize a daughter template chain.

Helicase, primase, and SSB proteins set the stage for synthesis. As a result, each of the chains of the original molecule becomes a matrix. Synthesis is carried out at a tremendous speed (from 50 nucleotides per second).

The work of DNA polymerase occurs in the direction from the 5' to the 3' end. Because of this, on one of the chains (leading) synthesis occurs in the course of unwinding and continuously, and on the other (lagging) - in the opposite direction and in separate fragments, called "Okazaki".

The Y-shaped structure formed at the site of DNA unwinding is called the replication fork.

Transcription mechanism

The key transcription enzyme is RNA polymerase. The latter is of several types and differs in structure in prokaryotes and eukaryotes. However, the mechanism of its action is the same everywhere and consists in building up a chain of complementary selected ribonucleotides with the closure of a phosphodiester bond between them.

The template molecule for this process is DNA. Based on it, one can create different types RNA, and not just informational, which are used in protein synthesis.

The site of the matrix from which the RNA sequence is "written off" is called the transcripton. It contains a promoter (a place for the attachment of RNA polymerase) and a terminator at which synthesis stops.

Broadcast

Matrix protein synthesis in both prokaryotes and eukaryotes is carried out in specialized organelles - ribosomes. The latter consist of two subunits, one of which (small) serves to bind tRNA and messenger RNA, and the other (large) takes part in the formation of peptide bonds.

The beginning of translation is preceded by the activation of amino acids, i.e., their attachment to the corresponding transport RNA with the formation of a macroergic bond, due to the energy of which transpeptidation reactions (attachment to the chain of the next link) are subsequently carried out.

Protein factors and GTP also take part in the synthesis process. The energy of the latter is necessary to move the ribosome along the RNA template chain.

The transmission and implementation of hereditary information is based on the reactions of matrix synthesis. There are only three of them: DNA replication, transcription and translation. All these reactions are related to plastic exchange reactions and require energy expenditure and the participation of enzymes.

Replication.

replication- self-doubling of DNA molecules - underlies the transmission of hereditary information from generation to generation. As a result of the replication of one parent DNA molecule, two daughter ones are formed, each of which is a double helix, in which one DNA strand is the parent one, and the other is newly synthesized. Replication requires various enzymes, nucleotides, and energy.

With the help of special enzymes, the hydrogen bonds connecting the complementary bases of the two strands of maternal DNA are broken. The strands of DNA diverge. Molecules of the DNA polymerase enzyme move along the parent DNA strands and sequentially connect nucleotides to form daughter DNA strands. The process of adding nucleotides follows the principle of complementarity. As a result, two DNA molecules are formed identical to the parent and to each other.

protein biosynthesis.

Protein biosynthesis, i.e. The process of realization of hereditary information proceeds in two stages. At the first stage, information about the primary structure of the protein is copied from DNA to mRNA. This process is called transcription. The second stage - translation - occurs on ribosomes. During translation, protein is synthesized from amino acids in accordance with the sequence recorded in mRNA, i.e. the nucleotide sequence is translated into an amino acid sequence. Thus, the process of realization of hereditary information can be expressed by the scheme:

DNA → mRNA → protein → property, trait

Transcription– synthesis of messenger RNA on a DNA template. This process takes place where there is DNA. In eukaryotes, transcription occurs in the nucleus, mitochondria, and chloroplasts (in plants), while in prokaryotes, directly in the cytoplasm. During transcription, the DNA molecule is the template, and the mRNA is the product of the reaction.

Transcription begins with the separation of DNA strands, which occurs in the same way as during replication (hydrogen bonds are broken with the help of enzymes). Then the RNA polymerase enzyme sequentially combines the nucleotides into a chain according to the principle of complementarity, synthesizing an mRNA molecule. The resulting mRNA molecule is separated and sent to the cytoplasm "in search of" the ribosome.

Protein synthesis on ribosomes is called broadcast. Translation in eukaryotes occurs on ribosomes located in the cytoplasm, on the surface of the EPS, in mitochondria and in chloroplasts (in plants), and in prokaryotes on ribosomes in the cytoplasm. Translation involves mRNA, tRNA, ribosomes, amino acids, ATP molecules, and enzymes.

· Amino acids serve as a material for the synthesis of a protein molecule.

· ATP is a source of energy for connecting amino acids with each other.

· Enzymes participate in the attachment of amino acids to tRNA and in the connection of amino acids with each other.

· Ribosomes They consist of rRNA and protein molecules that form an active center in which the main events of translation take place.

· Messenger RNA V this case is a template for the synthesis of a protein molecule. mRNA triplets, each of which codes for an amino acid, are called codons.

· Transfer RNAs bring amino acids to ribosomes and participate in the translation of the nucleotide sequence into the amino acid sequence. Transfer RNAs, like other types of RNA, are synthesized on a DNA template. They look like a clover leaf (Fig. 28.3). Three nucleotides located at the top of the central loop of the tRNA molecule form anticodon.

Translation progress.

Translation begins with the binding of mRNA to the ribosome. The ribosome moves along the mRNA, moving one triplet each time. Two triplets (codons) of mRNA can simultaneously be in the active center of the ribosome. Each of these codons is matched by a tRNA that has a complementary anticodon and carries a specific amino acid. Hydrogen bonds form between codons and anticodons, holding the tRNA in the active site. At this time, a peptide bond is formed between amino acids. The growing polypeptide chain is "suspended" on the tRNA, which entered the active center of the latter. The ribosome advances one triplet, resulting in a new codon and corresponding tRNA in the active site. The released tRNA is separated from the mRNA and sent for a new amino acid.

Biology Olympiad. school stage. 2016-2017 academic year.

10-11 grade

1. Wrong correlation of cell and tissue is

A) root hair - integumentary tissue

B) cell of the polysade parenchyma - the main tissue

C) trailing cell - integumentary tissue

D) companion cell - excretory tissue

2. For the event, which will take place in three days, ripe pears are needed. However, those pears that were bought for this purpose were not yet ripe. The ripening process can be accelerated by putting them

A) in a dark place

B) in the refrigerator

B) on the windowsill

D) in a bag of thick paper along with ripe apples

3. Bryophytes managed to survive on land because

A) they were the first plants to develop stomata

B) they do not require a moist environment for the reproductive cycle

C) they grow low above the soil in relatively humid regions

D) the sporophyte became independent of the gametophyte

4 Mammal Cheeks Are Formed Like

A) a device for collecting large amounts of food

B) the result of structural features of the skull, and in particular, the jaws

B) a sucking device

D) breathing aid

5. The heart of a crocodile in its structure

A) three-chamber with an incomplete septum in the ventricle

B) three-chamber

B) four-chamber

D) four-chamber with a hole in the septum between the ventricles

6. Fibrinogen, which is a protein, is involved in blood clotting

A) blood plasma

B) cytoplasm of leukocytes

B) part of platelets

D) formed during the destruction of red blood cells

7. Abiotic factors include such an ecological unit as

A) biocenosis

B) ecosystem

B) population

8. Reduction division (meiosis) occurs during the formation

A) bacterial spores

B) zoospores of ulotrix

B) marchantia spores

D) zoospores phytophthora

9. Of the listed biopolymers, a branched structure has

D) polysaccharides

10. Phenylketonuria is a genetic disease caused by a recessive mutation. The probability of having a sick child, if both parents are heterozygous for this trait, is

11. The similarity in the structure of the organs of vision in cephalopods and vertebrates is explained

A) convergence

B) parallelism

B) adaptation

D) a coincidence

12. A free-swimming ascidian larva has a chord and a neural tube. In an adult ascidia leading a sedentary lifestyle, they disappear. This is an example

A) adaptations

B) degeneration

B) cenogenesis

13. The water-carrying elements of pine are

A) annular and spiral vessels

B) only annular vessels

B) tracheids

D) spiral and porous vessels

14. Fertility is typical for

B) pineapple

B) a banana

15. In chloroplasts plant cells light harvesting complexes are located

A) on the outer membrane

B) on the inner membrane

B) on the thylakoid membrane

D) in the stroma

Part 2.

Match (6 points).

2.1. Establish a correspondence between the sign of the gray rat and the criterion of the species for which it is characteristic.

2.2. Establish a correspondence between the characteristics of the regulation of functions and its method.

Set the correct sequence (6 points).

2.3. Establish the correct sequence of stages of geographic speciation.

1) the emergence of territorial isolation between populations of the same species

2) expansion or division of the range of the species

3) the appearance of mutations in isolated populations

4) save natural selection individuals with traits that are useful in specific environmental conditions

5) loss by individuals of different populations of the ability to interbreed

2.4. Establish the sequence in which these processes occur during mitotic cell division.

1) chromosomes are located along the equator of the cell

2) chromatids diverge towards the poles of the cell

3) two daughter cells are formed

4) chromosomes are spiralized, each consists of two chromatids

5) chromosomes are despiralized

2.5. You are offered test tasks in the form of judgments, with each of which one must either agree or reject. In the response matrix, indicate the answer option “yes” or “no”: (10 points).

1. Nightshade flowers are collected in an umbrella inflorescence.

2. Ciliary worms do not have an anus.

3. Peroxisome is an obligatory organelle of a eukaryotic cell.

4. The peptide bond is not macroergic.

5. In liver cells, the addition of glucagon causes the breakdown of glycogen.

6. Abiotic factors do not affect the competitive relations of two related species.

7. The functions of gas exchange at the leaf are possible due to lenticels and hydathodes.

8. The section of the stomach of ruminants, corresponding to the single-chamber stomach of mammals, is the scar.

9. Length food chains limits energy loss.

10. The smaller the diameter of the blood vessels in the body, the greater the linear velocity of blood flow in them.

Part 3

3.1. Find three errors in the given text. Indicate the numbers of the proposals in which they are made, correct them (6 points).

1. Matrix synthesis reactions include starch formation, mRNA synthesis, protein assembly in ribosomes. 2. Matrix synthesis resembles the casting of coins on a matrix: new molecules are synthesized in exact accordance with the “plan” laid down in the structure of existing molecules. 3. The role of the matrix in the cell is played by chlorophyll molecules, nucleic acids (DNA and RNA). 4. Monomers are fixed on the matrices, then they are combined into polymer chains. 5. Finished polymers exit the matrices. 6. Old matrices are immediately destroyed, after which new ones are formed.

A person has four phenotypes according to blood groups: I (0), II (A), III (B), IV (AB). The gene that determines the blood group has three alleles: IA, IB, i0; moreover, the i0 allele is recessive with respect to the IA and IB alleles. Parents have II (heterozygous) and III (homozygous) blood groups. Determine the genotypes of the blood groups of the parents. Specify the possible genotypes and phenotypes (number) of the blood group of children. Make a scheme for solving the problem. Determine the probability of inheritance in children of the II blood group.

Answers grade 10-11

Part 1. Choose one correct answer. (15 points)

2.2. maximum - 3 points, one mistake - 2 points, two mistakes - 1b, three or more mistakes - 0 points

2.4. maximum - 3 points, one mistake - 2 points, two mistakes - 1b, three or more mistakes - 0 points

Part 3

3.1. Find three errors in the given text. Indicate the numbers of sentences in which they were made, correct them (3b for correct detection of sentences with errors and 3b for correcting errors).

1. - reactions of matrix synthesis do NOT include the formation of starch, a matrix is ​​not needed for it;

3. - chlorophyll molecules are not capable of acting as a matrix, they do not have the property of complementarity;

6. - matrices are used repeatedly.

3.2. Solve the problem (3 points).

The scheme for solving the problem includes:

1) parents have blood groups: group II - IAi0 (gametes IA, i0), group III - IB IB (gametes IB);

2) possible phenotypes and genotypes of children's blood groups: group IV (IAIB) and group III (IBi0);

3) the probability of inheritance of the II blood group is 0%.

Answer form

school stage All-Russian Olympiad in biology

Participant code _____________

Part 1. Choose one correct answer. (15 points)

Part 2.

Part 3

3.1._______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

3.2. The solution of the problem