Task 3 biology exam theory. Solving problems on the inheritance of sex-linked traits

Section in the codifier “Organism as a biological system”.

The task belongs to the basic level, if done correctly, you can get 1 point for it.

Topics given in the codifier:

3.1 Diversity of organisms: unicellular and multicellular; autotrophs, heterotrophs, aerobes, anaerobes.

3.2 Reproduction of organisms, its significance. Methods of reproduction, similarities and differences between sexual and asexual reproduction. Fertilization in flowering plants and vertebrates. External and internal fertilization.

3.3 Ontogeny and its inherent patterns. Embryonic and postembryonic development of organisms. Causes of disruption in the development of organisms.

3.4 Genetics, its tasks. Heredity and variability are properties of organisms. Methods of genetics. Basic genetic concepts and symbolism. Chromosomal theory of heredity. Modern ideas about the gene and genome.

3.5 Patterns of heredity, their cytological basis. Patterns of inheritance established by G. Mendel, their cytological foundations (mono- and dihybrid crossing). Laws of T. Morgan: linked inheritance of traits, violation of the linkage of genes. Sex genetics. Inheritance of sex-linked traits. Interaction of genes. The genotype as an integral system. Human genetics. Methods for studying human genetics. Solution of genetic problems. Drawing up cross-breeding schemes.

3.6 Regularities of variability. Non-hereditary (modification) variability. reaction rate. Hereditary variability: mutational, combinative. Types of mutations and their causes. The value of variability in the life of organisms and in evolution.

3.7 The value of genetics for medicine. Human hereditary diseases, their causes, prevention. The harmful effects of mutagens, alcohol, drugs, nicotine on the genetic apparatus of the cell. Protection of the environment from pollution by mutagens. Identification of sources of mutagens in the environment (indirectly) and assessment of the possible consequences of their influence on one's own body.

3.8 Selection, its tasks and practical significance. Contribution of N.I. Vavilov in the development of breeding: the doctrine of the centers of diversity and the origin of cultivated plants; law of homologous series in hereditary variability. Selection methods and their genetic bases. Methods for breeding new varieties of plants, animal breeds, strains of microorganisms. The value of genetics for selection. Biological bases for growing cultivated plants and domestic animals.

3.9 Biotechnology, its directions. Cellular and genetic engineering, cloning. The role of cell theory in the formation and development of biotechnology. The importance of biotechnology for the development of breeding, agriculture, the microbiological industry, and the preservation of the planet's gene pool. Ethical aspects of the development of some research in biotechnology (human cloning, directed changes in the genome).

There are really a lot of topics, however, the task is far from the most difficult. This is one of the few tasks that you can get the hang of, how to solve an example in mathematics. Naturally, this requires a certain amount of knowledge, but you yourself will see that, unlike other tasks, there are not so many of them.

Tasks are given either for calculations, or you need to specify the amount of something.

Analysis of typical tasks No. 3 USE in biology

There are 9 types of tasks. The figure, of course, is not the smallest, but for such a variant of exercises it is better to single out as many types as possible, because this makes it possible to refresh knowledge or get it and master this number once and for all.

Number of amino acids along the length of a DNA fragment

The length of a bacterial DNA molecule fragment is 20.4 nm. How many amino acids will be in the protein encoded by this DNA fragment?

Note.

The length of one nucleotide is 0.34 nm.

Pay attention to the note, it is clearly here for a reason.

So, now we have a practical task in mathematics from elementary school.

Our first action: We have beads, the length of which is 20.4 units. The diameter of one bead is 0.34 units. How many beads are there? Naturally, you just need to divide all the beads by the size of one of their components:

We found the number of nucleotides. The genetic code has such a property as tripletity. It is an amino acid encoded by three nucleotides. To find out the number of amino acids, you need to break the nucleotides into groups of three:

There will be 20 amino acids in a protein with a DNA fragment length of 20.4 nm.

An algorithm for a similar task:

Divide the length of the fragment by the length of one nucleotide. Get the number of nucleotides in the chain.
We divide the resulting number by three according to the property of triplicity.

PS: The sequence of nucleotides that defines an amino acid is called a codon.

Number of nucleotides by number of amino acids

How many nucleotides in a gene region encode a protein fragment of 25 amino acid residues? Write down the correct number for your answer.

Since one amino acid is coded for by three nucleotides, then 1 amino acid = 3 nucleotides

Number of amino acids by number of nucleotides

How many amino acids does 900 nucleotides encode. Write down the correct number for your answer.

Triplet again. 1 amino acid = 3 nucleotides. Divide all nucleotides by 3 to get amino acids.

Answer: 300.

Calculation of the percentage of certain nucleotides

In a DNA molecule, the number of nucleotides with guanine is 20% of the total. How many nucleotides in % with thymine in this molecule. Write down the correct number for your answer.

In this task, you need to remember another property of the genetic code: the property of complementarity. It means that nucleotides have pairs. Imagine DNA. Each chain is made up of nucleotides linked by hydrogen bonds. But the location is no coincidence.

Pairs in DNA:

Adenine-Thymine

Guanine - Cytosine

Pairs in RNA:

Adenine - Uracil

Guanine Cytosine

Since we have given that 20% of the total number is guanine, then this means that 20% falls on its complementary cytosine.

20% + 20% = 40% - guanine and cytosine.

For adenine and thymine remains:

60% - for adenine and thymine, and the question is only about thymine, which means that the number must be divided by 2:

30% - for thymine

30% - for adenine

You can solve the same and a little shorter. Since the percentage of each type of nucleotide is the same within a pair, then you can immediately count from 50 percent. From them it will be necessary to subtract only the percentage of nucleotides given by the condition from the other pair.

Writing a codon according to the principle of complementarity

Which transfer RNA anticodon corresponds to the TGA triplet in the DNA molecule?

Here you can develop an algorithm. If a DNA molecule is given, but you need to find tRNA, then you need:

write messenger RNA (mRNA) according to the principle of complementarity
write down transport DNA according to the principle of complementarity.

In our example:

Thymine corresponds to adenine

Guanine-cytosine

Adenine-uracil, because it's RNA

Adenine corresponds to uracil

Cytosine-guanine

Uracil - adenine

Answer: UGA

Even if it seemed that you could skip a step, it’s better not to, you can easily make a mistake, so write everything down.

The number of DNA molecules depending on the phase of division

Determine the number of DNA molecules in the anaphase of the second division of meiosis during the formation of gametes in a green frog, if the number of chromosomes in a diploid cell is 26. In response, write down only the number.

Understanding or memorizing the formulas of mitosis and meiosis will help here:

The condition refers to the number of chromosomes in a diploid cell. A diploid cell contains a double set of chromosomes. In the diagrams, n is the number of chromosomes, c is the number of chromatids.

In prophase, when the cell has not yet divided, it has a set of 2n4c, and in anaphase 2n2c.

We had 26n52с, according to the scheme, the number of chromosomes did not change, the number of chromatids changed: it decreased by half:

Number of chromosomes in a zygote

In the nuclei of the cells of the intestinal mucosa of a vertebrate animal, there are 20 chromosomes. What number of chromosomes will the nucleus of the zygote of this animal have? Write down the correct number for your answer.

Mucosal cells have a diploid set of chromosomes: 2n4c

20 chromosomes 40 chromatids.

A zygote is a fertilized egg cell with the formula 2n4c, that is, the same as a mucosal cell.

The number of chromosomes and chromatids in a zygote is different from the number of chromosomes and chromatids in a somatic cell.

Number of chromosomes in germ cells

In the fruit fly Drosophila, somatic cells contain 8 chromosomes, and in germ cells? Write down the correct number for your answer.

Somatic cells are diploid, and sex cells are haploid, because when they merge, they form a zygote, from which the organism develops. Half of the chromosomes from mom, half from dad. Normally, no more, no less, so it's easy to remember.

Once in the somatic 8, then in the sexual:

The number of cells formed as a result of division

How many cells are formed as a result of mitosis of one cell? Write down the correct number for your answer.

During mitosis, one cell produces two, with identical genetic material.

Characteristics of the types of tasks of part 3 (C) in the exam in biology

Compiled

Teacher MBOU "Secondary School No. 15"

the city of Engels

Myadelets M.V.

The meaning of tasks with free deployed answer

1. Tasks of this type make it possible not only to assess the educational achievements of graduates, the depth of their knowledge, but also to identify the logic of their reasoning, the ability to apply the acquired knowledge in non-standard situations, establish cause-and-effect relationships, generalize, substantiate, draw conclusions, think logically, clearly and briefly to the point of the question to state the answer.

2. Unlike tasks with a choice of answers, when performing this type of tasks, prompting or guessing the correct answer is excluded. Students must independently formulate the answer to the question posed.

3. Tasks of this type are of great importance for differentiating students according to their level of preparation, for establishing the formation of skills in graduates that characterize high-level cognitive activity, stages of the thought process, and identifying typical mistakes.

Types of free-response tasks

The exam uses different job types with free answer:

with two response elements (raised level); they suggest a short free response;
with three or more response items (high level); they suggest a full detailed answer.

Part 3 (C) contains 6 tasks with a free detailed answer: 1 - advanced and 5 - high level.

Tasks are evaluated according to the maximum points 2 And 3 .

Types of evaluation criteria free response tasks

The exam paper uses two types of evaluation criteria free response tasks:

With open range of requirements: the standard offers an approximate correct answer and indicates: “Other wordings of the answer are allowed that do not distort its meaning.” In this case, the correct answer can be given in other words.
With closed set of requirements positions" .

Tasks with two response elements

assigned to assignments increased level of complexity ,
suppose short free response in the form of several sentences,
evaluated according to the correctness 0 , 1 , 2 points.

These are tasks for the application of biological knowledge in practical situations (practice-oriented tasks)

control

knowledge across all blocks of content,
skill to apply in practical situations biological knowledge about living systems, biological patterns, characteristic features of organisms and superorganismal systems, the driving forces of evolution.

Graduates must substantiate nature conservation measures, hygiene practices and healthy lifestyle skills, apply knowledge about the structure and life of organisms from different kingdoms of wildlife in practice when growing plants and breeding animals, preserving biodiversity, etc.

Part C1 assignments

C1 Wind-pollinated trees and shrubs often bloom before the leaves bloom. Their stamens tend to produce much more pollen than insect pollinators. Explain what it is about.

Response elements:

1) the leaves would create an additional barrier to the pollination of these

plants, so they bloom earlier;

2) the formation of a large amount of pollen increases the likelihood of pollination and fertilization, since part of it is lost, settling on the soil, tree trunks, etc.

Items with three or more response items

assigned to assignments high level of complexity ,
suppose full deployed answer,
are estimated from 0 before 3

directed to check:

Ability to independently operate with biological concepts, substantiate and explain biological processes and phenomena, correctly formulate your answer;

Ability to apply knowledge in a new situation; establish causal relationships; analyze, systematize and integrate knowledge; summarize and formulate conclusions;

Ability to solve biological problems, evaluate and predict biological processes, apply theoretical knowledge in practice.

high level of complexity;
3 points;
check the ability to work with text and pictures, or analyze the text of biological content, identify errors and correct them by suggesting the correct wording;
also traditionally in this block a lot of attention is paid to the assessment of knowledge on the systematics and the most important properties of types and classes of animals and plants;

For successful implementation For such tasks, it is necessary to have the ability to carefully read the text, analyze it and correctly formulate your thoughts in writing.

C2 What processes are shown in Figures A and B? Name the cell structure involved in these processes. What transformations will occur next with the bacterium in Figure A?

rice. And fig. B

Response elements:

1) A - phagocytosis (capture of solid particles by the cell); B - pinocytosis (capture of liquid drops);

2) the plasma membrane of the cell is involved in these processes;

3) the phagocytic vesicle will merge with the lysosome, its contents will undergo splitting (lysis); the resulting monomers enter the cytoplasm

Part C3 assignments

high level of complexity;
contain three or more elements of a free detailed answer and are evaluated as much as possible in 3 points.
involve checking the ability to generalize and apply knowledge in the areas of biology:

The diversity of life on the planet;

life processes occurring at the organismic level in representatives of various kingdoms of wildlife and man;

when solving these tasks, students must demonstrate knowledge of the features of taxa and link them with the ecological and evolutionary characteristics of the group.

C3 How is the neurohumoral regulation of the separation of gastric juice in the human body? Explain the answer.

Response elements:

1) nervous regulation is carried out with direct irritation of the receptors of the oral cavity and stomach (unconditioned reflex);

2) nervous regulation is carried out when the receptors are stimulated

visual, auditory, olfactory analyzers (conditioned reflex);

3) humoral regulation: the breakdown products of organic food substances are absorbed into the blood and through the blood act on the glands of the stomach

Tasks C4

high level of complexity
contain three or more elements of a free detailed answer and are evaluated as much as possible in 3 points,
involve the generalization and application of knowledge in a new situation about the evolution of the organic world and environmental patterns.

Special difficulties elicit answers from graduates to the following groups of questions:

identification of the reasons for the adaptability of organisms to the environment;
explanation of the role of biological diversity in maintaining the balance in nature;
determination of biological and anthropogenic environmental factors that hinder the growth of populations;

C4 The rate of photosynthesis depends on factors such as light, carbon dioxide concentration, water, and temperature. Why are these factors limiting for photosynthesis reactions?

Response elements:

1) light is a source of energy for the light reactions of photosynthesis, with

its deficiency reduces the intensity of photosynthesis;

2) carbon dioxide and water are necessary for the synthesis of glucose, when they

deficiency reduces the intensity of photosynthesis;

3) all photosynthesis reactions are carried out with the participation of enzymes, the activity of which depends on temperature

Tasks C 5, C 6

assigned to assignments high level of complexity ,
suppose full deployed answer,
are estimated from 0 before 3 points depending on the completeness of the answer,

These are tasks for solving problems in cytology and genetics for the application of knowledge in a new situation.

They are related to tasks closed set of requirements: the standard offers the only correct answer, other interpretations are not allowed and it is indicated: The correct answer must contain the following positions" . In the answers to such tasks, all the items indicated in the standard answer must be present.

The exception is the use by the examinee of a different alphabetic symbolism in solving genetic problems

Tasks C5

these are tasks in cytology and molecular biology.

When solving them, students must show not only knowledge O

cell division (mitosis and meiosis),
gametogenesis in plants and animals
plant development cycles
alternation of sexual and asexual generation,

but also skills apply this knowledge to specific situations.

I task type is devoted to working with the table of the genetic code, and also requires the graduate to have knowledge of the processes of transcription and translation.

II task type is based on knowledge about changes in the cell's genetic makeup during mitosis and meiosis.

III task type based on knowledge of the life cycle of plants.

The tasks of determining the number of chromosomes in sex and somatic cells turned out to be especially difficult. When answering them, it is necessary not only to indicate the numerical value of chromosomes and DNA molecules, but also to give explanations.

The scheme for solving the problem includes

1) We determine the sequence of the i-RNA chain by the sequence of t-RNA molecules, using the principle of complementarity:

tRNA anticodons: AGC, ACC, GUA, CUA, CGA

2) We determine the amino acid sequence of the synthesized fragment of the protein molecule using the table of the genetic code by codons of i-RNA:

i-RNA codons: UCG-UGG-CAU-GAU-GCU

Amino acids: ser - three - gis - asp - ala

3) Determine the nucleotide sequence of a section of a double-stranded DNA molecule. The first chain is determined by the principle of complementarity based on mRNA, the second chain by the principle of complementarity based on the first DNA strand.

i-RNA codons: UCG-UGG-CAU-GAU-GCU

Double-stranded DNA fragment: DNA I: AGC-ACC-GTA-CTA-CGA

II DNA: TSH-THG-CAT-GAT-HCT

C5 The somatic cell of an animal is characterized by a diploid set of chromosomes. Determine the chromosome set (n) and the number of DNA molecules (c) in the cell at the end of meiosis telophase I and meiosis anaphase II. Explain the results in each case.

1) at the end of the telophase of meiosis I, the set of chromosomes is n; DNA number, 2s;

2) in the anaphase of meiosis II, the set of chromosomes is 2n; DNA number, 2s;

3) at the end of telophase I, reductional division occurred, the number of chromosomes and DNA decreased by 2 times, the chromosomes are two-chromatid;

4) in the anaphase of meiosis II, sister chromatids (chromosomes) diverge to the poles, so the number of chromosomes is equal to the number of DNA

C5. The chromosome set of wheat somatic cells is 28. Determine the chromosome set and the number of DNA molecules in one of the cells of the ovule before the start of meiosis, in the anaphase of meiosis 1 and in the anaphase of meiosis 2. Explain what processes occur during these periods and how they affect the change in the number of DNA and chromosomes.

The scheme for solving the problem includes:

1) before the start of meiosis, the number of DNA molecules is 56, since replication occurs and the number of DNA doubles, the number of chromosomes does not change - 28, but each chromosome consists of two chromatids;

2) in anaphase of meiosis 1, the number of DNA molecules is 56, the number of chromosomes is 28, homologous two-chromatid chromosomes diverge to the poles of the cell, but all chromosomes are in one cell;

3) in anaphase of meiosis 2, the number of DNA is 28, chromosomes - 28, after meiosis 1, the number of DNA and chromosomes decreased by 2 times, sister single-chromatid chromosomes diverge to the poles of the cell.

C5. What chromosome set is typical for the cell nuclei of the leaf epidermis and the eight-nuclear embryo sac of the ovule of a flowering plant? Explain from what initial cells and as a result of what division these cells are formed.

The scheme for solving the problem includes:

1) the set of chromosomes of the cells of the leaf epidermis is 2n, since the cells of all organs of the plant develop from the embryo (zygote) by mitosis;

2) the nuclei (cells) of the eight-nuclear embryo sac have n chromosomes, since the cells of the eight-nuclear embryo sac are formed from the haploid megaspore as a result of mitosis

C5. What chromosome set is typical for gametes and spores of the cuckoo flax moss plant? Explain from which cells and as a result of what division they are formed.

The scheme for solving the problem includes:

1) Cuckoo flax moss gametes are formed on gametophytes from a haploid cell by mitosis. The set of chromosomes in gametes is single (haploid) n.

2) Cuckoo flax moss spores are formed on a diploid sporophyte in sporangia by meiosis from diploid cells. The set of chromosomes in spores is single (haploid) n

Tasks C6

These are genetics questions.

When solving genetic problems, it is necessary to have clear ideas

about dominant and recessive traits,
about allelic genes
about analyzing crosses,
about heterogametic and homogametic (it must be remembered that in birds, female organisms are heterogametic.)

When solving genetic problems, it is necessary:

draw up a crossbreeding scheme, which should indicate

parents' genotypes
gametes,
genotypes and phenotypes of offspring,

explain the results
indicate which law is manifested in a particular case,
the answer sheet should present the progress of solving the problem, without which it is impossible to obtain the correct elements of the answer.

Tasks C6

This block contains tasks of several types:

I type - to determine the number of types of gametes

II type - for monohybrid crossing

III type - for dihybrid crossing (the law of independent inheritance of traits);

IV type - for sex-linked inheritance of traits;

Type V - to determine blood groups and Rh factor;

VI type - for linked inheritance;

VII type - for the analysis of pedigrees;

VIII type - problems of mixed type.

The first two types are most common in Part A (questions A7, A8 and A30).
Task types 3, 4, 5 and 6 make up the majority of C6 questions in the USE.
The sixth type of tasks - the most difficult tasks for the analysis of pedigrees;
The eighth type is tasks in which the inheritance of two pairs of traits is considered: one pair is linked to the X chromosome (or determines human blood groups), and the genes of the second pair of traits are located in autosomes. This class of tasks is also considered the most difficult for graduates.

C6 In humans, the gene for normal hearing (B) dominates the gene for deafness and is located in the autosome; the gene for color blindness (color blindness - d) is recessive and linked to the X chromosome. In a family where the mother suffered from deafness, but had normal color vision, and the father had normal hearing (homozygous), color blind, a girl was born with normal hearing, but color blind. Make a scheme for solving the problem. Determine the genotypes of parents, daughters, possible genotypes of children and their ratio. What patterns of heredity are manifested in this case?

The scheme for solving the problem includes:

1) genotypes of parents:

P ♀ bbX D X d × ♂ VV X d Y

G bX D , bX d B X d , B Y

2) possible genotypes of children:

F1 ВbX D X d – a girl with normal hearing and vision 25%;

ВbX d X d – girl with normal hearing, colorblind 25%;

BbX D Y – a boy with normal hearing and vision 25%;

ВbX d Y – a boy with normal hearing and vision 25%.

3) the law of independent inheritance of traits and sex-linked inheritance of trait is manifested

Task

Determine the nature of the inheritance of the trait and arrange the genotypes of all members of the pedigree.

Solution

1. Determine the type of trait inheritance.

The trait shows up in every generation. From marriage 1-2, where the father is the carrier of the trait, a son was born who has the analyzed trait. This indicates that this trait is dominant. A confirmation of the dominant type of inheritance of a trait is the fact that from the marriages of parents who do not carry the analyzed trait, children also do not have it.

2. Determine whether the trait is autosomal or sex-linked.

Both males and females are equally carriers of the trait. This indicates that this trait is autosomal.

3. We determine the genotypes of the members of the pedigree.

We introduce the designations of genes: A - dominant allele, a - recessive allele. In the offspring from marriages in which one of the parents carries the trait, splitting is observed in a ratio of 1: 1, which corresponds to splitting in analyzing crosses. This indicates the heterozygosity of the owners of the trait, that is, their genotype Ah. Persons in whom the trait is not observed - genotype aa.

Answer: the trait is inherited in an autosomal dominant manner. Trait holders have a genotype Ah, other members of the pedigree aa .

The biology exam is one of the selective ones and those who are confident in their knowledge will take it. The exam in biology is considered a difficult subject, as knowledge accumulated over the years of study is tested.

The tasks of the USE in biology are selected to be of different types; to solve them, confident knowledge of the main topics of the school biology course is required. On the basis of the teachers developed over 10 test tasks for each topic.

See the topics that you need to study when completing assignments from FIPI. For each task, its own algorithm of actions is prescribed, which will help in solving problems.

Changes in KIM USE 2019 in biology:

The task model in line 2 has been changed. Instead of a task with multiple choice for 2 points, a task for working with a table for 1 point has been included.
The maximum primary score decreased by 1 and amounted to 58 points.

The structure of the USE tasks in biology:

Part 1- these are tasks from 1 to 21 with a short answer, up to about 5 minutes are allotted for completion.

Advice: Read the wording of the questions carefully.

Part 2- these are tasks from 22 to 28 with a detailed answer, approximately 10-20 minutes are allotted for completion.

Advice: express your thoughts in a literary way, answer the question in detail and comprehensively, give a definition of biological terms, even if this is not required in the assignments. The answer should have a plan, not write in solid text, but highlight points.

What is required of the student in the exam?

Ability to work with graphic information (diagrams, graphs, tables) - its analysis and use;
Multiple choice;
Establishing compliance;
Sequencing.

Points for each task in USE biology

In order to get the highest grade in biology, you need to score 58 primary points, which will be converted to one hundred on a scale.

1 point - for 1, 2, 3, 6 tasks.
2 points - 4, 5, 7-22.
3 points - 23-28.

How to Prepare for Biology Tests

repetition of the theory.
Proper allocation of time for each task.
Solving practical problems several times.
Checking the level of knowledge by solving tests online.

Register, study and get a high score!

Write down the job number first (C1etc.), then the answer to it. For task C1, give a shortfree answer, and for tasks C2-C6 - full detailedanswer For answers to the tasks of this part (С1--С6), useanswer sheet number 2..

C1. The introduction of large doses of drugs into a vein is accompanied by their dilution with saline (0.9% N301 solution). Explain why.

The molecular structure of what monomer is shown in the diagram below?

What are the letters A, B, C?

3. Name the types of biopolymers that include this monomer.

SZ. Name at least 3 signs of adaptability of reptiles to reproduction in the terrestrial environment.

C4. How is the participation of functional groups of organisms in the cycle of substances in the biosphere manifested? Consider the role of each of them in the cycle of substances in the biosphere.

C5. The wasp fly is similar in color and body shape to a wasp. Name the type of its protective device, explain its significance and the relative nature of fitness.

Sat. A diheterozygous pea plant with smooth seeds and tendrils was crossed with a plant with wrinkled seeds without tendrils. It is known that both dominant genes (smooth seeds and the presence of antennae) are localized on the same chromosome; crossing over does not occur. Make a scheme for solving the problem. Determine the genotypes of the parents, the phenotypes and genotypes of the offspring, the ratio of individuals with different genotypes and phenotypes. What law is manifested in this

Part 3

For answers to the tasks of this part (C1-C6), use the answer sheet No. 2. First write down the number of the task (C1, etc.), then the answer to it. For task C1, give a short free answer, and for tasks C2-C6-full detailed answer.

C1. The dog has developed a conditioned salivary reflex to a light signal. During the supply of a conditioned stimulus (lighting a light bulb), a sharp loud sound is heard, and the conditioned reflex (saliva) does not appear. What phenomenon is described and what is its mechanism?

C2. The house mouse is a mammal of the genus Mice. Initial range - North Africa, tropics and subtropics of Eurasia; followed by man spread everywhere. Under natural conditions, it feeds on seeds. Leads a nocturnal and twilight lifestyle. Usually 5 to 7 babies are born in a litter. What type criteria are described in the text? Explain the answer.

SZ. Why does plowing the soil improve the living conditions of cultivated plants?

C4. Explain why people of different races are classified as the same species.

C5. 30 tRNA molecules participated in the translation process. Determine the number of amino acids that make up the synthesized protein, as well as the number of triplets and nucleotides in the gene that codes for this protein.

Sat. Cat coat color genes are located on the X chromosome. The black color is determined by the Xb gene, the red color is determined by the Xb gene, heterozygotes are tortoiseshell. From a black cat and a red cat were born: one tortoiseshell and one black kitten. Make a scheme for solving the problem. Determine the genotypes of parents and offspring, the possible sex of the kittens.

Tasks of the C1-C4 part

1. What environmental factors contribute to the regulation of the number of wolves in the ecosystem?

Answer:
1) anthropogenic: deforestation, overshooting;
2) biotic: lack of food, competition, spread of diseases.

2. Determine the type and phase of cell division shown in the figure. What processes take place in this phase?

Answer:
1) the figure shows the metaphase of mitosis;
2) spindle fibers are attached to the centromeres of chromosomes;
3) in this phase, two-chromatid chromosomes line up in the plane of the equator.

3. Why does plowing the soil improve the living conditions of cultivated plants?

Answer:
1) contributes to the destruction of weeds and weakens competition with cultivated plants;
2) contributes to the supply of plants with water and minerals;
3) increases the supply of oxygen to the roots.

4. How is a natural ecosystem different from an agroecosystem?

Answer:
1) great biodiversity and diversity of food relationships and food chains;
2) a balanced circulation of substances;
3) long periods of existence.

5. Expand the mechanisms that ensure the constancy of the number and shape of chromosomes in all cells of organisms from generation to generation?

Answer:
1) due to meiosis, gametes with a haploid set of chromosomes are formed;
2) during fertilization in the zygote, the diploid set of chromosomes is restored, which ensures the constancy of the chromosome set;
3) the growth of the organism occurs due to mitosis, which ensures the constancy of the number of chromosomes in somatic cells.

6. What is the role of bacteria in the cycle of substances?

Answer:
1) heterotrophic bacteria - decomposers decompose organic substances into minerals that are absorbed by plants;
2) autotrophic bacteria (photo, chemotrophs) - producers synthesize organic substances from inorganic ones, ensuring the circulation of oxygen, carbon, nitrogen, etc.

7. What are the characteristics of mossy plants?

Answer:

2) mosses reproduce both sexually and asexually with alternating generations: sexual (gametophyte) and asexual (sporophyte);
3) an adult moss plant is a sexual generation (gametophyte) and a box with spores is asexual (sporophyte);
4) fertilization occurs in the presence of water.

8. Squirrels, as a rule, live in a coniferous forest and feed mainly on spruce seeds. What biotic factors can lead to a reduction in the squirrel population?

9. It is known that the Golgi apparatus is especially well developed in the glandular cells of the pancreas. Explain why.

Answer:
1) in the cells of the pancreas, enzymes are synthesized that accumulate in the cavities of the Golgi apparatus;
2) in the Golgi apparatus, enzymes are packed in the form of bubbles;
3) from the Golgi apparatus, enzymes are carried into the pancreatic duct.

10. Ribosomes from different cells, the entire set of amino acids and the same molecules of mRNA and tRNA were placed in a test tube, and all the conditions for protein synthesis were created. Why will one type of protein be synthesized on different ribosomes in a test tube?

Answer:
1) the primary structure of a protein is determined by the sequence of amino acids;
2) templates for protein synthesis are the same mRNA molecules, in which the same primary protein structure is encoded.

11. What features of the structure are characteristic of representatives of the Chordata type?

Answer:
1) internal axial skeleton;
2) the nervous system in the form of a tube on the dorsal side of the body;
3) gaps in the digestive tube.

12. Clover grows in a meadow, pollinated by bumblebees. What biotic factors can lead to a decline in the clover population?

Answer:
1) a decrease in the number of bumblebees;
2) an increase in the number of herbivorous animals;
3) reproduction of plants of competitors (cereals, etc.).

13. The total mass of mitochondria in relation to the mass of cells of various organs of the rat is: in the pancreas - 7.9%, in the liver - 18.4%, in the heart - 35.8%. Why do the cells of these organs have a different content of mitochondria?

Answer:
1) mitochondria are the energy stations of the cell, ATP molecules are synthesized and accumulated in them;
2) for the intensive work of the heart muscle, a lot of energy is needed, therefore the content of mitochondria in its cells is the highest;
3) in the liver, the number of mitochondria is higher compared to the pancreas, since it has a more intensive metabolism.

14. Explain why beef that has not passed sanitary control is dangerous to eat undercooked or lightly fried.

Answer:
1) in beef meat there may be finns of bovine tapeworm;
2) in the digestive canal, an adult worm develops from the Finn, and the person becomes the final owner.

15. Name the plant cell organoid shown in the figure, its structures, indicated by numbers 1-3, and their functions.

Answer:
1) the depicted organoid is a chloroplast;
2) 1 - grana thylakoids, participate in photosynthesis;
3) 2 - DNA, 3 - ribosomes, are involved in the synthesis of their own chloroplast proteins.

16. Why bacteria cannot be classified as eukaryotes?

Answer:
1) in their cells, the nuclear substance is represented by one circular DNA molecule and is not separated from the cytoplasm;
2) do not have mitochondria, Golgi complex, EPS;
3) do not have specialized germ cells, there are no meiosis and fertilization.

17. What changes in biotic factors can lead to an increase in the population of the naked slug that lives in the forest and feeds mainly on plants?

18. In the leaves of plants, the process of photosynthesis proceeds intensively. Does it occur in mature and unripe fruits? Explain the answer.

Answer:
1) photosynthesis occurs in immature fruits (while they are green), since they contain chloroplasts;
2) as they mature, chloroplasts turn into chromoplasts, in which photosynthesis does not occur.

19. What stages of gametogenesis are indicated in the figure by the letters A, B and C? What set of chromosomes do cells have at each of these stages? To the development of what specialized cells does this process lead?

Answer:
1) A - stage (zone) of reproduction (division), diploid cells;
2) B - growth stage (zone), diploid cell;
3) B - stage (zone) of maturation, haploid cells, spermatozoa develop.

20. How do bacterial cells differ in structure from the cells of organisms of other kingdoms of wildlife? List at least three differences.

Answer:
1) there is no formed core, nuclear membrane;
2) a number of organelles are absent: mitochondria, ER, Golgi complex, etc.;
3) have one ring chromosome.

21. Why are plants (producers) considered the initial link in the circulation of substances and the transformation of energy in an ecosystem?

Answer:
1) create organic substances from inorganic;
2) accumulate solar energy;
3) provide organic matter and energy to the organisms of other parts of the ecosystem.

22. What processes ensure the movement of water and minerals through the plant?

Answer:
1) from the root to the leaves, water and minerals move through the vessels due to transpiration, which results in a sucking force;
2) the upward current in the plant is promoted by root pressure, which occurs as a result of the constant flow of water to the root due to the difference in the concentration of substances in the cells and the environment.

23. Consider the cells shown in the figure. Determine what letters denote prokaryotic and eukaryotic cells. Provide evidence for your point of view.

Answer:
1) A - prokaryotic cell, B - eukaryotic cell;
2) the cell in figure A does not have a formed nucleus, its hereditary material is represented by a ring chromosome;
3) the cell in figure B has a well-formed nucleus and organelles.

24. What is the complication of the circulatory system of amphibians compared to fish?

Answer:
1) the heart becomes three-chambered;
2) the second circle of blood circulation appears;
3) the heart contains venous and mixed blood.

25. Why is a mixed forest ecosystem considered more sustainable than a spruce forest ecosystem?

Answer:
1) there are more species in a mixed forest than in a spruce forest;
2) in a mixed forest, food chains are longer and more branched than in a spruce forest;
3) there are more tiers in a mixed forest than in a spruce forest.

26. A section of a DNA molecule has the following composition: GATGAATAGTGCTTC. List at least three consequences that an accidental replacement of the seventh nucleotide of thymine with cytosine (C) can lead to.

Answer:
1) a gene mutation will occur - the codon of the third amino acid will change;
2) in a protein, one amino acid can be replaced by another, as a result, the primary structure of the protein will change;
3) all other protein structures can change, which will lead to the appearance of a new trait in the body.

27. Red algae (crimson) live at great depths. Despite this, photosynthesis occurs in their cells. Explain how photosynthesis occurs if the water column absorbs the rays of the red-orange part of the spectrum.

Answer:
1) for photosynthesis, rays are needed not only in the red, but also in the blue part of the spectrum;
2) purple cells contain a red pigment that absorbs the rays of the blue part of the spectrum, their energy is used in the process of photosynthesis.

28. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them.
1. Coelenterates are three-layer multicellular animals. 2. They have a gastric or intestinal cavity. 3. The intestinal cavity includes stinging cells. 4. Coelenterates have a mesh (diffuse) nervous system. 5. All intestinal - free-floating organisms.

1) 1 - coelenterates - two-layer animals;
2)3 - stinging cells are contained in the ectoderm, and not in the intestinal cavity;
3)5 - among the coelenterates there are attached forms.

29. How does gas exchange occur in the lungs and tissues in mammals? What is the reason for this process?

Answer:
1) gas exchange is based on diffusion, which is due to the difference in the concentration of gases (partial pressure) in the air of the alveoli and in the blood;
2) oxygen from the area of high pressure in the alveolar air enters the blood, and carbon dioxide from the area of high pressure in the blood enters the alveoli;
3) in the tissues, oxygen from the high pressure area in the capillaries enters the intercellular substance and then into the cells of the organs. Carbon dioxide from the area of high pressure in the intercellular substance enters the blood.

30. What is the participation of functional groups of organisms in the circulation of substances in the biosphere? Consider the role of each of them in the cycle of substances in the biosphere.

Answer:
1) producers synthesize organic substances from inorganic substances (carbon dioxide, water, nitrogen, phosphorus and other minerals), release oxygen (except for chemotrophs);
2) consumers (and other functional groups) of organisms use and convert organic substances, oxidize them during respiration, absorbing oxygen and releasing carbon dioxide and water;
3) decomposers decompose organic substances to inorganic compounds of nitrogen, phosphorus, etc., returning them to the environment.

31. A section of a DNA molecule encoding a sequence of amino acids in a protein has the following composition: G-A-T-G-A-A-T-A-G-TT-C-T-T-C. Explain the consequences of accidentally adding a guanine (G) nucleotide between the seventh and eighth nucleotides.

Answer:
1) a gene mutation will occur - the codes of the third and subsequent amino acids may change;
2) the primary structure of the protein may change;
3) a mutation can lead to the appearance of a new trait in an organism.

32. What plant organs are damaged by May beetles at different stages of individual development?

Answer:
1) plant roots damage larvae;
2) tree leaves damage adult beetles.

33. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them.
1. Flatworms are three-layered animals. 2. Type Flatworms include white planaria, human roundworm and liver fluke. 3. Flatworms have an elongated flattened body. 4. They have a well-developed nervous system. 5. Flatworms are dioecious animals that lay eggs.

Mistakes made in sentences:
1) 2 - the type of Flatworms does not include the human roundworm, it is a Roundworm;
2) 4 - in flatworms, the nervous system is poorly developed;
3) 5 - Flatworms - hermaphrodites.

34. What is a fetus? What is its significance in the life of plants and animals?

Answer:
1) fruit - generative organ of angiosperms;
2) contains seeds, with the help of which the reproduction and resettlement of plants occurs;
3) the fruits of plants are food for animals.

35. Most of the bird species fly away for the winter from the northern regions, despite their warm-bloodedness. Name at least three factors that cause these animals to migrate.

Answer:
1) food objects of insectivorous birds become unavailable for getting;
2) ice cover on water bodies and snow cover on the ground deprive herbivorous birds of food;
3) change in the length of daylight hours.

36. Which milk, sterilized or freshly milked, will go sour faster under the same conditions? Explain the answer.

Answer:
1) freshly milked milk will sour faster, as it contains bacteria that cause fermentation of the product;
2) when milk is sterilized, cells and spores of lactic acid bacteria die, and milk is stored longer.

37. Find errors in the given text. Indicate the numbers of sentences in which errors were made, explain them.
1. The main classes of the type of arthropods are Crustaceans, Arachnids and Insects. 2. The body of crustaceans and arachnids is divided into head, thorax and abdomen. 3. The body of insects consists of a cephalothorax and an abdomen. 4. Spider antennae don't. 5. Insects have two pairs of antennae, while crustaceans have one pair.

Mistakes made in sentences:
1) 2 - the body of crustaceans and arachnids consists of a cephalothorax and abdomen;
2)3 - the body of insects consists of a head, chest and abdomen;
3-5 - insects have one pair of antennae, and crustaceans have two pairs.

38. Prove that the rhizome of a plant is a modified shoot.

Answer:
1) the rhizome has nodes in which there are rudimentary leaves and buds;
2) at the top of the rhizome is the apical bud, which determines the growth of the shoot;
3) adventitious roots depart from the rhizome;
4) the internal anatomical structure of the rhizome is similar to the stem.

39. Man uses chemicals to control pests. Indicate at least three changes in the life of an oak forest if all herbivorous insects are destroyed in it by a chemical method. Explain why they will happen.

Answer:
1) the number of insect pollinated plants will decrease sharply, since herbivorous insects are pollinators of plants;
2) the number of insectivorous organisms (consumers of the second order) will sharply decrease or they will disappear due to disruption of food chains;
3) part of the chemicals used to kill insects will enter the soil, which will lead to disruption of plant life, death of soil flora and fauna, all violations can lead to the death of oak forests.

40. Why can antibiotic treatment lead to bowel dysfunction? Name at least two reasons.

Answer:
1) antibiotics kill beneficial bacteria that live in the human intestine;
2) fiber breakdown, water absorption and other processes are disturbed.

41. What part of the sheet is indicated in the figure by the letter A and what structures does it consist of? What are the functions of these structures?

1) the letter A denotes a vascular fibrous bundle (vein), the bundle includes vessels, sieve tubes, mechanical tissue;
2) vessels provide water transport to the leaves;
3) sieve tubes provide transport of organic substances from leaves to other organs;
4) mechanical tissue cells give strength and are the framework of the sheet.

42. What are the characteristic features of the fungi kingdom?

Answer:
1) the body of fungi consists of filaments - hyphae, forming a mycelium;
2) reproduce sexually and asexually (spores, mycelium, budding);
3) grow throughout life;
4) in the cell: the shell contains a chitin-like substance, a reserve nutrient - glycogen.

43. In a small reservoir formed after the flood of the river, the following organisms were found: ciliates-shoes, daphnia, white planarians, a large pond snail, cyclops, hydras. Explain whether this body of water can be considered an ecosystem. Give at least three pieces of evidence.

Answer:
The named temporary reservoir cannot be called an ecosystem, since in it:
1) there are no producers;
2) there are no decomposers;
3) there is no closed circulation of substances and food chains are broken.

44. Why is a note placed under the tourniquet, which is applied to stop bleeding from large blood vessels, indicating the time of its application?

Answer:
1) after reading the note, you can determine how much time has passed since the tourniquet was applied;
2) if after 1-2 hours it was not possible to deliver the patient to the doctor, then the tourniquet should be loosened for a while. This will prevent tissue necrosis.

45. Name the structures of the spinal cord, indicated in the figure by numbers 1 and 2, and describe the features of their structure and function.

Answer:
1) 1 - gray matter, formed by the bodies of neurons;
2) 2 - white matter, formed by long processes of neurons;
3) gray matter performs a reflex function, white matter - a conductive function.

46. What role do salivary glands play in digestion in mammals? List at least three functions.

Answer:
1) the secretion of the salivary glands moistens and disinfects food;
2) saliva is involved in the formation of the food bolus;
3) saliva enzymes contribute to the breakdown of starch.

47. As a result of volcanic activity, an island was formed in the ocean. Describe the sequence of ecosystem formation on a newly formed piece of land. List at least three items.

Answer:
1) the first to settle are microorganisms and lichens that provide soil formation;
2) plants settle on the soil, the spores or seeds of which are carried by wind or water;
3) as vegetation develops, animals appear in the ecosystem, primarily arthropods and birds.

48. Experienced gardeners apply fertilizer to the grooves located along the edges of the near-stem circles of fruit trees, and do not distribute them evenly. Explain why.

Answer:
1) the root system grows, the suction zone moves behind the root tip;
2) roots with a developed suction zone - root hairs - are located along the edges of the near-stem circles.

49. What modified shoot is shown in the picture? Name the elements of the structure, indicated in the figure by the numbers 1, 2, 3, and the functions that they perform.

Answer:
1) bulb;
2) 1 - juicy scaly leaf, in which nutrients and water are stored;
3) 2 - adventitious roots that ensure the absorption of water and minerals;
4) 3 - kidney, ensures the growth of the shoot.

50. What are the features of the structure and life of mosses? List at least three items.

Answer:
1) most mosses are leafy plants, some of them have rhizoids;
2) mosses have a poorly developed conducting system;
3) mosses reproduce both sexually and asexually, with alternation of generations: sexual (gametophyte) and asexual (sporophyte); an adult moss plant is a sexual generation, and a spore box is asexual.

51. As a result of a forest fire, part of the spruce forest burned out. Explain how it will self-heal. List at least three steps.

Answer:
1) herbaceous light-loving plants develop first;
2) then shoots of birch, aspen, pine appear, the seeds of which fell with the help of the wind, a small-leaved or pine forest is formed.
3) under the canopy of light-loving species, shade-tolerant spruces develop, which subsequently completely crowd out other trees.

52. To establish the cause of a hereditary disease, the patient's cells were examined and a change in the length of one of the chromosomes was found. What research method allowed to establish the cause of this disease? What kind of mutation is it associated with?

Answer:
1) the cause of the disease is established using the cytogenetic method;
2) the disease is caused by a chromosomal mutation - the loss or addition of a chromosome fragment.

53. What letter in the figure indicates the blastula in the development cycle of the lancelet. What are the features of blastula formation?

Answer:
1) the blastula is designated by the letter G;
2) the blastula is formed during the crushing of the zygote;
3) the size of the blastula does not exceed the size of the zygote.

54. Why are fungi isolated in a special kingdom of the organic world?

Answer:
1) the body of mushrooms consists of thin branching threads - hyphae, forming a mycelium, or mycelium;
2) mycelium cells store carbohydrates in the form of glycogen;
3) fungi cannot be attributed to plants, since their cells do not have chlorophyll and chloroplasts; the wall contains chitin;
4) mushrooms cannot be attributed to animals, since they absorb nutrients from the entire surface of the body, and do not swallow them in the form of food lumps.

55. In some forest biocenoses, mass shooting of diurnal birds of prey was carried out to protect chicken birds. Explain how this event affected the number of chickens.

Answer:
1) at first, the number of chickens increased, since their enemies (naturally regulating the number) were destroyed;
2) then the number of chickens decreased due to lack of food;
3) the number of sick and weakened individuals increased due to the spread of diseases and the absence of predators, which also affected the decrease in the number of chickens.

56. The color of the fur of a white hare changes throughout the year: in winter the hare is white, and in summer it is gray. Explain what type of variability is observed in an animal and what determines the manifestation of this trait.

Answer:
1) a manifestation of modification (phenotypic, non-hereditary) variability is observed in a hare;
2) the manifestation of this trait is determined by changes in environmental conditions (temperature, day length).

57. Name the stages of embryonic development of the lancelet, indicated in the figure by the letters A and B. Expand the features of the formation of each of these stages.
A B

Answer:
1) A - gastrula - the stage of a two-layer embryo;
2) B - neurula, has the beginnings of a future larva or adult organism;
3) the gastrula is formed by invagination of the blastula wall, and in the neurula, the neural plate is first laid, which serves as a regulator for laying the rest of the organ systems.

58. What are the main features of the structure and vital activity of bacteria. List at least four features.

Answer:
1) bacteria - pre-nuclear organisms that do not have a formalized nucleus and many organelles;
2) according to the method of nutrition, bacteria are heterotrophs and autotrophs;
3) high rate of reproduction by division;
4) anaerobes and aerobes;
5) unfavorable conditions are experienced in a state of dispute.

59. What is the difference between the ground-air environment and the water?

Answer:
1) oxygen content;
2) differences in temperature fluctuations (wide amplitude of fluctuations in the ground-air environment);
3) the degree of illumination;
4) density.

Answer:
1) seaweed has the ability to accumulate the chemical element iodine;
2) Iodine is essential for normal thyroid function.

61. Why is a shoe ciliate cell considered an integral organism? What organelles of ciliates-shoes are indicated in the figure by the numbers 1 and 2 and what functions do they perform?

Answer:
1) the ciliate cell performs all the functions of an independent organism: metabolism, reproduction, irritability, adaptation;
2) 1 - a small nucleus, participates in the sexual process;
3) 2 - a large core, regulates vital processes.

61. What are the features of the structure and life of fungi? List at least three features.

62. Explain the harm to plants caused by acid rain. Give at least three reasons.

Answer:
1) directly damage the organs and tissues of plants;
2) pollute the soil, reduce fertility;
3) reduce the productivity of plants.

63. Why are passengers advised to suck on lollipops when taking off or landing an airplane?

Answer:
1) a rapid change in pressure during takeoff or landing of an aircraft causes discomfort in the middle ear, where the initial pressure on the eardrum lasts longer;
2) swallowing movements improve the access of air to the auditory (Eustachian) tube, through which the pressure in the middle ear cavity equalizes with the pressure in the environment.

64. How does the circulatory system of arthropods differ from the circulatory system of annelids? Indicate at least three signs that prove these differences.

Answer:
1) in arthropods, the circulatory system is open, and in annelids it is closed;
2) arthropods have a heart on the dorsal side;
3) annelids do not have a heart, its function is performed by an annular vessel.

65. What type is the animal shown in the picture? What is indicated by numbers 1 and 2? Name other representatives of this type.

Answer:
1) to the type of intestinal;
2) 1 - ectoderm, 2 - intestinal cavity;
3) coral polyps, jellyfish.

66. What are the morphological, physiological and behavioral adaptations to environmental temperature in warm-blooded animals?

Answer:
1) morphological: heat-insulating covers, subcutaneous fat layer, changes in the surface of the body;
2) physiological: increased intensity of evaporation of sweat and moisture during breathing; narrowing or dilation of blood vessels, changes in the level of metabolism;
3) behavioral: construction of nests, burrows, changes in daily and seasonal activity depending on the temperature of the environment.

67. How is the receipt of genetic information from the nucleus to the ribosome?

Answer:
1) mRNA synthesis occurs in the nucleus in accordance with the principle of complementarity;
2) mRNA - a copy of the DNA section containing information about the primary structure of the protein moves from the nucleus to the ribosome.

68. What is the complication of ferns in comparison with mosses? Give at least three signs.

Answer:
1) ferns have roots;
2) in ferns, unlike mosses, a developed conductive tissue has formed;
3) in the development cycle of ferns, the asexual generation (sporophyte) prevails over the sexual (gametophyte), which is represented by the outgrowth.

69. Name the embryonic layer of a vertebrate animal, indicated in the figure by the number 3. What type of tissue and what organs are formed from it.

Answer:
1) germinal layer - endoderm;
2epithelial tissue (intestinal and respiratory epithelium);
3) organs: intestines, digestive glands, respiratory organs, some endocrine glands.

70. What role do birds play in the biocenosis of the forest? Give at least three examples.

Answer:
1) regulate the number of plants (distribute fruits and seeds);
2) regulate the number of insects, small rodents;
3) serve as food for predators;
4) fertilize the soil.

71. What is the protective role of leukocytes in the human body?

Answer:
1) leukocytes are capable of phagocytosis - devouring and digesting proteins, microorganisms, dead cells;
2) leukocytes are involved in the production of antibodies that neutralize certain antigens.

72. Find errors in the given text. Indicate the numbers of the proposals in which they are made, correct them.
According to the chromosome theory of heredity:
1. Genes are located on chromosomes in a linear order. 2. Everyone occupies a certain place - an allele. 3. Genes on one chromosome form a linkage group. 4. The number of linkage groups is determined by the diploid boron of chromosomes. 5. Violation of gene linkage occurs in the process of conjugation of chromosomes in the prophase of meiosis.

Mistakes made in sentences:
1)2 - location of the gene - locus;
2)4 - the number of linkage groups is equal to the haploid set of chromosomes;
3)5 - disruption of gene linkage occurs during crossing over.

73. Why do some scientists refer to green euglena as a plant, and others as an animal? List at least three reasons.

Answer:
1) capable of heterotrophic nutrition, like all animals;
2) capable of active movement in search of food, like all animals;
3) contains chlorophyll in the cell and is capable of autotrophic nutrition, like plants.

74. What processes take place at the stages of energy metabolism?

Answer:
1) at the preparatory stage, complex organic substances are split into less complex ones (biopolymers - to monomers), energy is dissipated in the form of heat;
2) in the process of glycolysis, glucose is broken down to pyruvic acid (or lactic acid, or alcohol) and 2 ATP molecules are synthesized;
3) at the oxygen stage, pyruvic acid (pyruvate) is broken down to carbon dioxide and water and 36 ATP molecules are synthesized.

75. In a wound formed on the human body, bleeding eventually stops, but suppuration may occur. Explain what properties of blood this is due to.

Answer:
1) bleeding stops due to blood clotting and the formation of a blood clot;
2) suppuration is due to the accumulation of dead leukocytes that have carried out phagocytosis.

76. Find errors in the given text, correct them. Indicate the numbers of sentences in which errors were made, explain them.
1. Proteins are of great importance in the structure and life of organisms. 2. These are biopolymers whose monomers are nitrogenous bases. 3. Proteins are part of the plasma membrane. 4. Many proteins perform an enzymatic function in the cell. 5. In protein molecules, hereditary information about the characteristics of an organism is encrypted. 6. Protein and tRNA molecules are part of ribosomes.

Mistakes made in sentences:
1) 2 - protein monomers are amino acids;
2)5 - hereditary information about the characteristics of the organism is encrypted in DNA molecules;
3)6- ribosomes contain rRNA molecules, not tRNA.

77. What is myopia? In what part of the eye is the image focused in a nearsighted person? What is the difference between congenital and acquired forms of myopia?

Answer:
1) myopia is a disease of the organs of vision, in which a person does not distinguish distant objects;
2) in a nearsighted person, the image of objects appears in front of the retina;
3) with congenital myopia, the shape of the eyeball changes (lengthens);
4) acquired myopia is associated with a change (increase) in the curvature of the lens.

78. What is the difference between the skeleton of the human head and the skeleton of the head of great apes? List at least four differences.

Answer:
1) the predominance of the brain of the skull over the facial;
2) reduction of the jaw apparatus;
3) the presence of a chin protrusion on the lower jaw;
4) reduction of superciliary arches.

79. Why is the volume of urine excreted by the human body per day not equal to the volume of liquid drunk during the same time?

Answer:
1) part of the water is used by the body or is formed in metabolic processes;
2) part of the water evaporates through the respiratory organs and sweat glands.

80. Find errors in the given text, correct them, indicate the numbers of the sentences in which they are made, write down these sentences without errors.
1. Animals are heterotrophic organisms; they feed on ready-made organic substances. 2. There are unicellular and multicellular animals. 3. All multicellular animals have bilateral body symmetry. 4. Most of them have developed various organs of locomotion. 5. Only arthropods and chordates have a circulatory system. 6. Postembryonic development in all multicellular animals is direct.

Mistakes made in sentences:
1) 3 - not all multicellular animals have bilateral symmetry of the body; for example, in coelenterates it is radial (radial);
2) 5 - the circulatory system is also present in annelids and mollusks;
3) 6 - direct postembryonic development is not inherent in all multicellular animals.

81. What is the importance of blood in human life?

Answer:
1) performs a transport function: delivery of oxygen and nutrients to tissues and cells, removal of carbon dioxide and metabolic products;
2) performs a protective function due to the activity of leukocytes and antibodies;
3) participates in the humoral regulation of the vital activity of the organism.

82. Use information about the early stages of embryogenesis (zygote, blastula, gastrula) to confirm the sequence of development of the animal world.

Answer:
1) the zygote stage corresponds to a unicellular organism;
2) the blastula stage, where cells are not differentiated, is similar to colonial forms;
3) the embryo at the gastrula stage corresponds to the structure of the intestinal cavity (hydra).

83. The introduction of large doses of drugs into a vein is accompanied by their dilution with saline (0.9% NaCl solution). Explain why.

Answer:
1) the introduction of large doses of drugs without dilution can cause a sharp change in the composition of the blood and irreversible phenomena;
2) the concentration of physiological saline (0.9% NaCl solution) corresponds to the concentration of salts in the blood plasma and does not cause the death of blood cells.

84. Find errors in the given text, correct them, indicate the numbers of the sentences in which they are made, write down these sentences without errors.
1. Animals of the arthropod type have an outer chitinous cover and jointed limbs. 2. The body of most of them consists of three sections: the head, chest and abdomen. 3. All arthropods have one pair of antennae. 4. Their eyes are complex (faceted). 5. The circulatory system of insects is closed.

Mistakes made in sentences:
1)3 - not all arthropods have one pair of antennae (arachnoids do not have them, and crustaceans have two pairs each);
2) 4 - not all arthropods have compound (compound) eyes: in arachnids they are simple or absent, in insects, along with compound eyes, they can be simple;
3-5 - the circulatory system in arthropods is not closed.

85. What are the functions of the human digestive system?

Answer:
1) mechanical processing of food;
2) chemical processing of food;
3) movement of food and removal of undigested residues;
4) absorption of nutrients, mineral salts and water into the blood and lymph.

86. What characterizes biological progress in flowering plants? List at least three features.

Answer:
1) a wide variety of populations and species;
2) wide settlement on the globe;
3) adaptability to life in different environmental conditions.

87. Why should food be chewed thoroughly?

Answer:
1) well-chewed food is quickly saturated with saliva in the oral cavity and begins to be digested;
2) well-chewed food is quickly saturated with digestive juices in the stomach and intestines and therefore easier to digest.

88. Find errors in the given text. Indicate the numbers of the proposals in which they are made, correct them.
1. A population is a collection of freely interbreeding individuals of the same species that inhabit a common territory for a long time. 2. Different populations of the same species are relatively isolated from each other, and their individuals do not interbreed. 3. The gene pool of all populations of the same species is the same. 4. The population is the elementary unit of evolution. 5. A group of frogs of the same species living in a deep puddle for one summer is a population.

Mistakes made in sentences:
1)2 - populations of the same species are partially isolated, but individuals of different populations can interbreed;
2)3 — gene pools of different populations of the same species are different;
3)5 - a group of frogs is not a population, since a group of individuals of the same species is considered a population if it occupies the same space for a large number of generations.

89. Why is it recommended to drink salted water in summer with prolonged thirst?

Answer:
1) in summer, sweating increases in a person;
2) mineral salts are excreted from the body with sweat;
3) salted water restores the normal water-salt balance between the tissues and the internal environment of the body.

90. What proves that a person belongs to the class of mammals?

Answer:
1) the similarity of the structure of organ systems;
2) the presence of hairline;
3) the development of the embryo in the uterus;
4) feeding offspring with milk, caring for offspring.

91. What processes maintain the constancy of the chemical composition of human blood plasma?

Answer:
1) processes in buffer systems maintain the reaction of the medium (pH) at a constant level;
2) neurohumoral regulation of the chemical composition of plasma is carried out.

92. Find errors in the given text. Indicate the numbers of the proposals in which they are made, explain them.
1. A population is a collection of freely interbreeding individuals of different species that have inhabited a common territory for a long time. 2. The main group characteristics of a population are the number, density, age, sex and spatial structures. 3. The totality of all the genes of a population is called the gene pool. 4. Population is a structural unit of living nature. 5. The number of populations is always stable.

Mistakes made in sentences:
1)1 - a population is a collection of freely interbreeding individuals of the same species, inhabiting the common territory of the population for a long time;
2)4 - the population is a structural unit of the species;
3-5 - the number of populations can change in different seasons and years.

93. What structures of the integument of the body provide protection for the human body from the effects of environmental temperature factors? Explain their role.

Answer:
1) subcutaneous fatty tissue protects the body from cooling;
2) sweat glands form sweat, which, when evaporated, protects against overheating;
3) the hair on the head protects the body from cooling and overheating;
4) changing the lumen of skin capillaries regulates heat transfer.

94. Give at least three progressive biological features of a person, which he acquired in the process of long evolution.

Answer:
1) an increase in the brain and cerebral part of the skull;
2) upright posture and corresponding changes in the skeleton;
3) liberation and development of the hand, opposition of the thumb.

95. What division of meiosis is similar to mitosis? Explain how it is expressed and what set of chromosomes in the cell leads to.

Answer:
1) similarity with mitosis is observed in the second division of meiosis;
2) all phases are similar, sister chromosomes (chromatids) diverge to the poles of the cell;
3) the resulting cells have a haploid set of chromosomes.

96. What is the difference between arterial bleeding and venous bleeding?

Answer:
1) with arterial bleeding, scarlet blood;
2) it shoots out of the wound with a strong jet, a fountain.

97. The scheme of what process occurring in the human body is shown in the figure? What underlies this process and how does the composition of the blood change as a result? Explain the answer.
capillary

Answer:
1) the figure shows a diagram of gas exchange in the lungs (between the pulmonary vesicle and the blood capillary);
2) gas exchange is based on diffusion - the penetration of gases from a place with high pressure to a place with less pressure;
3) as a result of gas exchange, the blood is saturated with oxygen and turns from venous (A) to arterial (B).

98. What effect does hypodynamia (low motor activity) have on the human body?

Answer:
hypodynamia leads to:
1) to a decrease in the level of metabolism, an increase in adipose tissue, overweight;
2) weakening of the skeletal and cardiac muscles, increasing the load on the heart and reducing the endurance of the body;
3) venous blood stagnation in the lower extremities, vasodilation, circulatory disorders.

(Other formulations of the answer are allowed that do not distort its meaning.)

99. What are the characteristics of plants that live in arid conditions?

Answer:
1) the root system of plants penetrates deep into the soil, reaches the groundwater or is located in the surface layer of the soil;
2) in some plants, water is stored in leaves, stems and other organs during drought;
3) the leaves are covered with a wax coating, pubescent or modified into spines or needles.

100. What is the reason for the need for iron ions to enter the human blood? Explain the answer.

Answer:

2) erythrocytes provide transport of oxygen and carbon dioxide.

101. Through what vessels and what kind of blood enters the chambers of the heart, indicated in the figure by numbers 3 and 5? With what circle of blood circulation is each of these structures of the heart connected?

Answer:
1) venous blood enters the chamber marked with the number 3 from the superior and inferior vena cava;
2) the chamber marked with the number 5 receives arterial blood from the pulmonary veins;
3) the chamber of the heart, indicated by the number 3, is associated with a large circle of blood circulation;
4) the chamber of the heart, indicated by the number 5, is associated with the pulmonary circulation.

102. What are vitamins, what is their role in the life of the human body?

Answer:
1) vitamins - biologically active organic substances needed in small quantities;
2) they are part of enzymes, participating in metabolism;
3) increase the body's resistance to adverse environmental influences, stimulate growth, development of the body, restoration of tissues and cells.

103. The body shape of the Kalima butterfly resembles a leaf. How did a similar body shape form in a butterfly?

Answer:
1) the appearance in individuals of various hereditary changes;
2) preservation by natural selection of individuals with a modified body shape;
3) reproduction and distribution of individuals with a body shape resembling a leaf.

104. What is the nature of most enzymes and why do they lose their activity when the level of radiation increases?

Answer:
1) most enzymes are proteins;
2) under the action of radiation, denaturation occurs, the structure of the protein-enzyme changes.

105. Find errors in the given text. Indicate the numbers of proposals in which they are made, correct them.
1. Plants, like all living organisms, feed, breathe, grow, reproduce. 2. According to the method of nutrition, plants are classified as autotrophic organisms. 3. When breathing, plants absorb carbon dioxide and release oxygen. 4. All plants reproduce by seeds. 5. Plants, like animals, grow only in the first years of life.

Mistakes made in sentences:
1) 3 - when breathing, plants absorb oxygen and release carbon dioxide;
2-4 - only flowering and gymnosperms reproduce by seeds, and algae, mosses, ferns - by spores;
3-5 - plants grow throughout their lives, have unlimited growth.

106. What is the reason for the need for iron ions to enter the human blood? Explain the answer.

Answer:
1) iron ions are part of the hemoglobin of erythrocytes;
2) erythrocyte hemoglobin provides transport of oxygen and carbon dioxide, as it is able to bind to these gases;
3) the supply of oxygen is necessary for the energy metabolism of the cell, and carbon dioxide is its final product to be removed.

107. Explain why people of different races are classified as the same species. Give at least three pieces of evidence.

Answer:
1) the similarity of the structure, life processes, behavior;
2) genetic unity - the same set of chromosomes, their structure;
3) interracial marriages produce offspring capable of reproduction.

108. In ancient India, a person suspected of a crime was offered to swallow a handful of dry rice. If he did not succeed, the guilt was considered proven. Give a physiological justification for this process.

Answer:
1) swallowing is a complex reflex act, which is accompanied by salivation and irritation of the root of the tongue;
2) with strong excitement, salivation is sharply inhibited, the mouth becomes dry, and the swallowing reflex does not occur.

109. Find errors in the given text. Indicate the numbers of the proposals in which they are made, explain them.
1. The composition of the food chain of biogeocenosis includes producers, consumers and decomposers. 2. The first link in the food chain are consumers. 3. Consumers in the world accumulate energy absorbed in the process of photosynthesis. 4. In the dark phase of photosynthesis, oxygen is released. 5. Reducers contribute to the release of energy accumulated by consumers and producers.

Mistakes made in sentences:
1) 2 - the first link is the producers;
2) 3 - consumers are not capable of photosynthesis;
3)4 - oxygen is released in the light phase of photosynthesis.

110. What are the causes of anemia in humans? List at least three possible reasons.

Answer:
1) large blood loss;
2) malnutrition (lack of iron and vitamins, etc.);
3) violation of the formation of erythrocytes in the hematopoietic organs.

111. The wasp fly is similar in color and body shape to a wasp. Name the type of its protective device, explain its significance and the relative nature of fitness.

Answer:
1) type of adaptation - mimicry, imitation of the color and shape of the body of an unprotected animal to a protected one;
2) resemblance to a wasp warns a possible predator about the danger of being stung;
3) the fly becomes the prey of young birds that have not yet developed a reflex to the wasp.

112. Make up a food chain using all of the following objects: humus, cross-spider, hawk, great tit, housefly. Determine the consumers of the third order in the compiled chain.

Answer:
1) humus -> housefly -> spider-cross -> great tit -> hawk;
2) consumer of the third order - great tit.

113. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them.
1. Annelids are the most highly organized animals of the cut of other types of worms. 2. Annelids have an open circulatory system. 3. The body of the annelids consists of identical segments. 4. There is no body cavity in annelids. 5. The nervous system of annelids is represented by the peripharyngeal ring and the dorsal nerve chain.

Mistakes made in sentences:
1) 2 - Annelids have a closed circulatory system;
2) 4 - Annelids have a body cavity;
3-5 - the nerve chain is located on the ventral side of the body.

114. Name at least three aromorphoses in terrestrial plants that allowed them to be the first to master the land. Justify the answer.

Answer:
1) the emergence of integumentary tissue - the epidermis with stomata - contributing to protection against evaporation;
2) the appearance of a conducting system that ensures the transport of substances;
3) the development of a mechanical tissue that performs a supporting function.

115. Explain the reason for the great diversity of marsupials in Australia and their absence on other continents.

Answer:
1) Australia separated from other continents during the heyday of marsupials before the appearance of placental animals (geographical isolation);
2) the natural conditions of Australia contributed to the divergence of signs of marsupials and active speciation;
3) on other continents, marsupials were replaced by placental mammals.

116. In what cases does a change in the sequence of DNA nucleotides not affect the structure and functions of the corresponding protein?

Answer:
1) if, as a result of a nucleotide substitution, another codon appears that codes for the same amino acid;
2) if the codon formed as a result of a nucleotide substitution encodes another amino acid, but with similar chemical properties that does not change the structure of the protein;
3) if nucleotide changes occur in intergenic or non-functioning DNA regions.

117. Why is the relationship between pike and perch in the river ecosystem considered competitive?

Answer:
1) are predators, eat similar food;
2) live in the same reservoir, need similar conditions for life, mutually oppress each other.

118. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them.
1. The main classes of the type of arthropods are Crustaceans, Arachnids and Insects. 2. Insects have four pairs of legs, and arachnids have three pairs. 3. The crayfish has simple eyes, and the cross-spider has complex eyes. 4. In arachnids, spider warts are located on the abdomen. 5. Spider-cross and Maybug breathe with the help of lung sacs and trachea.

Mistakes made in sentences:
1) 2 - insects have three pairs of legs, and arachnids - four pairs;
2) 3 - crayfish has compound eyes, and the cross-spider has simple eyes;
3-5 - the May beetle does not have lung sacs, but only tracheae.

119. What are the features of the structure and life of cap mushrooms? List at least four features.

Answer:
1) have a mycelium and a fruiting body;
2) reproduce by spores and mycelium;
3) according to the method of nutrition - heterotrophs;
4) most form mycorrhiza.

120. What aromorphoses allowed the ancient amphibians to master the land.

Answer:
1) the appearance of pulmonary respiration;
2) the formation of dissected limbs;
3) the appearance of a three-chambered heart and two circles of blood circulation.