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Difficult exam topics in biology |
They were grouped into seven content blocks: Biology is the science of wildlife; Cell as a biological system; The organism as a biological system; System and diversity of the organic world; Man and his health; The evolution of living nature; Ecosystems and their inherent patterns. The examination paper consisted of three parts. Part 1 included 36 tasks with the choice of one correct answer out of four, of which 26 were basic and 10 were advanced levels of complexity. Part 2 - 8 high-level tasks: 3 - with the choice of several correct answers out of six, 3 - to establish a correspondence between biological objects, processes and phenomena, 2 - to determine the sequence of phenomena and processes. Part 3 consisted of 6 tasks with a detailed answer: 1 - advanced and 5 - high level. All tasks of part 3 controlled the ability of graduates to independently express their thoughts, solve biological problems, explain facts, use them to formulate a conclusion, generalization. In part 3, the following lines were highlighted: C1 - practice-oriented tasks; Block 1. Biology - the science of wildlifeThe task turned out to be difficult, requiring the determination of the level of organization of the living, at which protein structures are studied. Instead of the molecular level, students chose the cellular and organismal levels. The coniferous forest ecosystem was attributed by about half of the examinees to the biospheric level of life organization instead of the biocenotic one. Block 2. Cell as a biological systemThe greatest difficulties and problems arose for the USE participants when answering tasks that require comparison of eukaryotic and prokaryotic cells, RNA- and DNA-containing viruses, mitosis and meiosis, various phases of cell division, stages of energy metabolism; knowledge of the relationship between the structure and functions of organelles and chemical substances of the cell, their participation in metabolic processes; determination of the chromosome set of somatic and germ cells. Particular attention should be paid to the performance of task C5 by the examinees, which offered three types of tasks in cytology: the application of knowledge about the genetic code, the determination of the number of chromosomes and DNA in different phases of mitosis and meiosis, and the substantiation of metabolic processes. The examinees made a mistake when completing a task that required determining a fragment of a tRNA molecule and its anticodon by the nucleotide sequence of DNA, as well as determining the amino acid that this tRNA carries. The participants did not take into account the fact that the entire sequence of the mRNA fragment cannot be determined from a fragment of one tRNA molecule, but only its codon, which corresponds to the anticodon, can be determined. They split tRNA into triplets, determined mRNA by tRNA, and found the amino acid sequence from the obtained triplets. According to this answer, one tRNA molecule turned out to be simultaneously a template for the synthesis of mRNA and protein, which is a gross mistake. When preparing for the exam, you should review the material on protein biosynthesis, the translation process and the role of tRNA in it. The tasks of determining the number of chromosomes and DNA in different phases of mitosis and meiosis turned out to be especially difficult. Typical mistakes that were made include the following: 1) the concepts of DNA replication and chromosome doubling are identified. In interphase, before the start of division, the number of DNA molecules doubles, two sister chromatids are formed, but the number of chromosomes does not change, since the chromatids are linked by the centromere and make up one chromosome. The number of chromosomes in a cell increases and becomes equal to the number of DNA only in the anaphase of any division, since sister chromatids, separating, become sister chromosomes; 2) there is often no explanation for each phase of the division, which was required to be given according to the condition of the problem; 3) in a significant part of the work, the participants determined the number of chromosomes, but did not determine the number of DNA molecules, as was required in the condition of the problem. When performing tasks that required tracing the transformation of energy or the path of hydrogen in the process of metabolism, participants most often described the entire process, but did not answer the specific question provided for in the task. For example, in response to a task in which it was required to trace the path of hydrogen in the light and dark stages of photosynthesis from the moment of its formation to the synthesis of glucose, it was necessary to indicate: 1) the formation of hydrogen ions during the photolysis of water under the action of sunlight, 2) the combination of hydrogen with NADP+ carrier and the formation of NADP.2H, 3) the use of NADP.2H in the reduction reaction of intermediates from which glucose is synthesized. Block 3. Organism as a biological systemThe examinees found it difficult to define parthenogenesis as a special kind of sexual reproduction, which organisms it is inherent in. Serious problems arose in answering questions about the individual development of organisms. Many USE participants in biology do not know well the cycles of plant development, the alternation of gametophyte and sporophyte in mosses and ferns; find it difficult to compare the stages of development of the animal embryo (neurula and gastrula), to determine the sequence of processes occurring during gametogenesis. Particularly difficult were tasks in genetics, in which it was required to determine the chromosome set of the genome, its difference from the karyotype and genotype, the number of alleles in gametes, the ratio of offspring in monohybrid crossing. In order to avoid such mistakes in the future, it is recommended to repeat the material on meiosis before starting the study of genetics, since it underlies the formation of gametes and the inheritance of traits. Block 4. System and diversity of the organic worldPoorly learned material on the structure and vital activity of bacteria and fungi. In particular, the participants found it difficult to distinguish between bacteria and unicellular plants, to determine the mode of nutrition of decay bacteria. They did not master the concepts of "mycorrhiza", "symbiosis", they could not determine the mold fungus mukor from the drawing, although its image is in every biology textbook. Of the practice-oriented tasks (C1), the lowest indicators were found when completing the task on the causes of the spread of porcini mushrooms in forests. The examinees could not explain the reasons for the spread of fungi that form symbiosis with plants. Instead, environmental factors were named: heat, humidity, shading, soil characteristics. In the section “Plants”, the greatest difficulties were caused by questions of a physiological nature (transport of water, mineral and organic substances; the role of root pressure and transpiration in these processes), the principles of classification of flowering plants, aromorphic features of ferns, alternation of generations in higher spore plants. Most of the examinees coped poorly with task C2, which required to determine its characteristics and belonging to the dicotyledonous class from the drawing of strawberries. The participants correctly identified the class of the depicted plant, however, for this they did not use the drawing, but their knowledge of the features of the dicotyledonous class that were not shown in the drawing (two cotyledons, cambium in the stem, tap root system). They could not explain the formation of adventitious roots in strawberries, growing from the above-ground shoot (whiskers) and not being a sign of dicotyledonous plants, but pointed only to the tap root system with an undeveloped main root. Tasks that control knowledge about invertebrates remain traditionally difficult: signs of complication of annelids (the appearance of a closed circulatory system), isolation of the anterior end of the body due to the appearance of bilateral symmetry, features of bivalves (shell structure, pearl formation), insects with complete and incomplete transformation , the importance of the salivary glands in the formation of the cocoon and the pupal stage. Low results were also obtained in responses to individual questions of the Chordata type. Graduates do not know the type of nervous system of chordates, find it difficult to determine the parts of the brain of vertebrates from the drawing, cannot name the progressive features of mammals compared to reptiles, and explain the adaptability of amphibians to life in water and on land. When compiling the article, materials were used: Tasks of the C1-C4 part 1. What environmental factors contribute to the regulation of the number of wolves in the ecosystem? Answer: 2. Determine the type and phase of cell division shown in the figure. What processes take place in this phase? Answer: 3. Why does plowing the soil improve the living conditions of cultivated plants? Answer: 4. How is a natural ecosystem different from an agroecosystem? Answer: 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: 6. What is the role of bacteria in the cycle of matter? Answer: 7. What are the characteristics of mossy plants? Answer: 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: 10. Ribosomes from different cells, the entire set of amino acids and the same mRNA and tRNA molecules 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: 11. What features of the structure are characteristic of representatives of the Chordata type? Answer: 12. Clover grows in a meadow, pollinated by bumblebees. What biotic factors can lead to a decline in the clover population? Answer: 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: 14. Explain why beef that has not passed sanitary control is dangerous to eat undercooked or lightly fried. Answer: 15. Name the plant cell organoid shown in the figure, its structures, indicated by numbers 1-3, and their functions. Answer: 16. Why bacteria cannot be classified as eukaryotes? Answer: 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: 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: 20. How do bacterial cells differ in structure from the cells of organisms of other kingdoms of wildlife? List at least three differences. Answer: 21. Why are plants (producers) considered the initial link in the circulation of substances and the transformation of energy in an ecosystem? Answer: 22. What processes ensure the movement of water and minerals through the plant? Answer: 23. Consider the cells shown in the figure. Determine what letters denote prokaryotic and eukaryotic cells. Provide evidence for your point of view. Answer: 24. What is the complication of the circulatory system of amphibians in comparison with fish? Answer: 25. Why is a mixed forest ecosystem considered more sustainable than a spruce forest ecosystem? Answer: 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: 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: 28. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them.
29. How does gas exchange occur in the lungs and tissues in mammals? What is the reason for this process? Answer: 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: 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: 32. What plant organs are damaged by May beetles at different stages of individual development? Answer: 33. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them. Mistakes made in sentences: 34. What is a fetus? What is its significance in the life of plants and animals? Answer: 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: 36. Which milk, sterilized or freshly milked, will go sour faster under the same conditions? Explain the answer. Answer: 37. Find errors in the given text. Indicate the numbers of sentences in which errors were made, explain them. Mistakes made in sentences: 38. Prove that the rhizome of a plant is a modified shoot. Answer: 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: 40. Why can antibiotic treatment lead to bowel dysfunction? Name at least two reasons. Answer: 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; 42. What are the characteristic features of the fungi kingdom? Answer: 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: 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: 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: 46. What role do salivary glands play in digestion in mammals? List at least three functions. Answer: 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: 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: 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: 50. What are the features of the structure and life of mosses? List at least three items. Answer: 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: 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: 53. What letter in the figure indicates the blastula in the development cycle of the lancelet. What are the features of blastula formation? Answer: 54. Why are fungi isolated in a special kingdom of the organic world? Answer: 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: 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: 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. Answer: 58. What are the main features of the structure and vital activity of bacteria. List at least four features. Answer: 59. What is the difference between the ground-air environment and the water? Answer: Answer: 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: 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: 63. Why are passengers advised to suck on lollipops when taking off or landing an airplane? Answer: 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: 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: 66. What are the morphological, physiological and behavioral adaptations to environmental temperature in warm-blooded animals? Answer: 67. How is the receipt of genetic information from the nucleus to the ribosome? Answer: 68. What is the complication of ferns in comparison with mosses? Give at least three signs. Answer: 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: 70. What role do birds play in the biocenosis of the forest? Give at least three examples. Answer: 71. What is the protective role of leukocytes in the human body? Answer: 72. Find errors in the given text. Indicate the numbers of the proposals in which they are made, correct them. Mistakes made in sentences: 73. Why do some scientists refer to green euglena as a plant, and others as an animal? List at least three reasons. Answer: 74. What processes take place at the stages of energy metabolism? Answer: 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: 76. Find errors in the given text, correct them. Indicate the numbers of sentences in which errors were made, explain them. Mistakes made in sentences: 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: 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: 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: 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. Mistakes made in sentences: 81. What is the importance of blood in human life? Answer: 82. Use information about the early stages of embryogenesis (zygote, blastula, gastrula) to confirm the sequence of development of the animal world. Answer: 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: 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. Mistakes made in sentences: 85. What are the functions of the human digestive system? Answer: 86. What characterizes biological progress in flowering plants? List at least three features. Answer: 87. Why should food be chewed thoroughly? Answer: 88. Find errors in the given text. Indicate the numbers of the proposals in which they are made, correct them. Mistakes made in sentences: 89. Why is it recommended to drink salted water in summer with prolonged thirst? Answer: 90. What proves that a person belongs to the class of mammals? Answer: 91. What processes maintain the constancy of the chemical composition of human blood plasma? Answer: 92. Find errors in the given text. Indicate the numbers of the proposals in which they are made, explain them. Mistakes made in sentences: 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: 94. Give at least three progressive biological features of a person, which he acquired in the process of long evolution. Answer: 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: 96. What is the difference between arterial bleeding and venous bleeding? Answer: 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. Answer: 98. What effect does hypodynamia (low motor activity) have on the human body? Answer: (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: 100. What is the reason for the need for iron ions to enter the human blood? Explain the answer. Answer: 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: 102. What are vitamins, what is their role in the life of the human body? Answer: 103. The body shape of the Kalima butterfly resembles a leaf. How did a similar body shape form in a butterfly? Answer: 104. What is the nature of most enzymes and why do they lose their activity when the level of radiation increases? Answer: 105. Find errors in the given text. Indicate the numbers of proposals in which they are made, correct them. Mistakes made in sentences: 106. What is the reason for the need for iron ions to enter the human blood? Explain the answer. Answer: 107. Explain why people of different races are classified as the same species. Give at least three pieces of evidence. Answer: 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: 109. Find errors in the given text. Indicate the numbers of the proposals in which they are made, explain them. Mistakes made in sentences: 110. What are the causes of anemia in humans? List at least three possible reasons. Answer: 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: 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: 113. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them. Mistakes made in sentences: 114. Name at least three aromorphoses in terrestrial plants that allowed them to be the first to master the land. Justify the answer. Answer: 115. Explain the reason for the great diversity of marsupials in Australia and their absence on other continents. Answer: 116. In what cases does a change in the sequence of DNA nucleotides not affect the structure and functions of the corresponding protein? Answer: 117. Why is the relationship between pike and perch in the river ecosystem considered competitive? Answer: 118. Find errors in the given text. Indicate the numbers of sentences in which errors were made, correct them. Mistakes made in sentences: 119. What are the features of the structure and life of cap mushrooms? List at least four features. Answer: 120. What aromorphoses allowed the ancient amphibians to master the land. Answer: Assignments from the USE bank in biology with a free answer 1. The biological oxidation of organic substances in the human body is similar in chemical process to the combustion of fuel (coal, peat, wood). What products, common with combustion, are formed as a result of these processes? Compare the energetics of the processes of biological oxidation and combustion. What is their difference? 1) as a result of the oxidation of organic substances by oxygen, as in combustion, carbon dioxide and water are formed; 2) during combustion, all energy is released in the form of heat, and during biological oxidation, part of the energy is stored in ATP molecules 2. Why, according to the rule of the ecological pyramid, in the terrestrial food chain from link to link, there is a decrease in energy? 1) the energy contained in organic substances at each link in the food chain is spent on life processes; 2) part of the energy is dissipated in the form of heat. 3. Why does the nasal cavity need to be moist and clean for normal smell perception? Explain the answer. 1) the cavity must be moistened, since the olfactory cells (receptors) are irritated only by substances dissolved in the mucus of the nasal cavity; 2) abundant secretion of mucus prevents the access of substances to olfactory receptors 4. Make up a food chain using all the named representatives: cruciferous fleas, polecat, snake, turnip leaves, frog. Determine the consumer of the second order in the compiled chain and explain your choice. 1) turnip leaves → cruciferous fleas → frog → snake → polecat; 2) consumer of the second order - a frog, as it feeds on consumers of the first order Response elements: 1) wet seeds will begin to germinate, while they breathe intensively and release a lot of heat; 2) strong heating of a large number of seeds leads to the death of both germinated and non-germinated seeds 6. What are the formations on the roots of the depicted plant? What type of relationship between organisms does the picture illustrate? Explain the meaning these relationships for both organisms. Response elements: 1) formations on the roots of a leguminous plant - these are nodules containing nodule bacteria; 2) the type of mutually beneficial relationship - a symbiosis of bacteria (nitrogen-fixing bacteria) and a leguminous plant; 3) nodule bacteria feed on plant organic matter; 4) nodule bacteria fix atmospheric nitrogen and provide legumes with nitrogen compounds 7. Using the diagram, identify the isolation method that led to the emergence of three related subspecies of the great tit and explain its consequences. To what result of evolution can their reproductive isolation lead? Response elements: 1) geographical isolation led to the emergence of three subspecies of the great tit; 2) as a result of geographical isolation, interbreeding and gene exchange between individuals of different populations ceases, 3) Reproductive isolation can lead to the formation of three related species of tits 8. The figure shows a diagram of speciation according to Ch. Darwin. What evolutionary process leads to the formation of the new species shown in Figure III? What driving forces (factors) of evolution underlie this process? What form of natural selection takes place in this case? Response elements: 1) divergence (divergence) of signs; 2) divergence is due to hereditary variability, the struggle for existence and natural selection; 3) driving (disruptive) form of natural selection 8. Name the departments of the visual analyzer, indicated in the Figure by numbers 1 and 2. What function does each of these departments perform? Response elements: 1) 1 - peripheral section (or retina, or receptors); 2) 2 - conduction department (or optic nerve); 3) the retina perceives and converts light stimulation 4) the optic nerve transmits nerve impulses to the brain 9. Name the animal shown in the picture and indicate its type. What organ systems are marked with numbers 1 and 2? What functions do they perform? Response elements: 1) the lancelet is depicted; type Chordates; 2) 1 - the nervous system - is involved in the nervous regulation of all functions of the body and the relationship with the environment; 3) 2 - digestive system (gut) - digests food and absorbs nutrients 10. Find three errors in the given text. Indicate the numbers of sentences in which errors were made, correct them. 1. Fungi and bacteria are classified as prokaryotes. 2. There is a wide variety among fungi: yeasts, molds, cap mushrooms, etc. 3. A common feature of multicellular fungi is the formation of a vegetative body from thin branching filaments that form a mycelium. 4. A fungal cell has a cell wall consisting of chitin and membrane organelles. 5. The reserve nutrient is glycogen. 6. Mushrooms have an autotrophic type of nutrition. 7. Mushroom growth stops after spores mature. Response elements: Mistakes in sentences: 1) 1 - fungi are eukaryotes; 2) 6 - fungi have a heterotrophic type of nutrition; 3) 7 - mushrooms grow throughout life The thyroid gland regulates the exchange of potassium, as it greatly affects the functioning of the nervous system. The fact is that the transmission of a nerve impulse is based on the sodium-potassium pump, in which potassium and sodium ions migrate through the membrane. A similar question was in the test part of the USE 2017: it was necessary to match which of the two glands regulates potassium metabolism, the pancreas or the thyroid. The problem is that there was no clear answer to this question in any textbook and manual on biology. Dispute: embryo or cell? One of the students wrote that a spore is a single-celled plant embryo. This is not true. A spore is a haploid cell used for asexual reproduction or for spreading. What is the fate of the controversy? In plants, it divides by mitosis. For example, in flowering plants, the male spore turns after two mitoses into two sperm and a vegetative cell. And the female spore inside the flower divides by mitosis three times and ensures the formation of eight nuclei of the embryo sac of the ovule. The embryo in plants is formed from the zygote after fertilization. From it, a seed is formed in gymnosperms and flowering plants. I come to the conclusion that the tutor and parents need to check the hourly plan for preparing students' homework for each week. As soon as each student follows his plan persistently and strictly, the score on the exam will skyrocket. What does the genetic code encode? One of the students gave a strange explanation that "the table of the genetic code encodes mRNA." If something is encoded in it, then mRNA triplets encode amino acids. It is incorrect to write that the table itself encodes something. Now I am talking about a standard problem in cytology. The problem is that it requires an explanation. As you can see, students often write something strange. In a specific task, it was necessary to write as follows: “Amino acids are encoded by mRNA triplets that are complementary to tRNA anticodons. Let us find the CGU mRNA triplet by the HCA tRNA anticodon. Next, we look at the table for the amino acid that it encodes - Arg. This is the correct text of the answer, if you are given a tRNA anticodon in the task of cytology (question 27). Head of cabbage, "protein" shell and reproduction of amphibians The key idea of the answers to the exam in biology: you must give the most complete, detailed answer. Short, short answers are not appropriate. They rarely reveal the full meaning. For example, a student did not write that a head of cabbage is a modified shoot. Outcome: 1 point removed. Yes, the head of cabbage is actually also a kidney, but also an escape! And this is important to point out. In addition, we must remember that the kidney is a rudimentary shoot. In this case, a head of cabbage is not a typical kidney, but a modified one. Minor inaccuracies in the writing of the answer also lead to the loss of points. For example, a student wrote not “protein”, but “protein” shell. Ball removed. The "protein" shell of the eye does not exist. If you saw amphibians (frogs) in the picture that mate, this does not mean that they have internal fertilization. In many frogs, it is external (outer), like in most amphibians. But, of course, there are tailed amphibians with internal fertilization. Morphological changes arose in human ancestors Here is another bright question of the USE 2017. “What morphological changes arose in human ancestors in the process of the formation of upper limbs in order to make fire and use tools?” Perhaps the question in the reference version sounded a little differently. But while I have it in this form (passed by the students). 1. Development of a five-fingered upper limb of a grasping type and a hand with a large number of movable joints. 2. Opposition of the thumb to the others (and its development), which provides fine manipulations of the hands. 3. The development of the muscles of the upper limbs, the shoulder girdle, changes in the structure of the axial skeleton, limb girdles and free limbs (extension of the chest, shortening of the upper limbs, reduction in their size) - all this provided the hands with greater mobility. 4. An increase in the volume of the brain, the growth of the cerebral cortex provided a person with a more complex behavior necessary for conscious and labor activity. I see no point in commenting on every point. The only point: paragraph 3 could be expanded in more detail in terms of disclosing the changes due to upright posture. But note, this is a pretty general question. The process of limb formation went in parallel with the development of the brain, as described in paragraph 4. Let me remind you that in the USE question about changes in the skeleton due to work, we mention not only the opposition of the thumb, but also the predominance of the cerebral part of the skull over the facial. 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 Unified State Examination in Biology are selected to be of different types, for their solution, 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 structure of the USE tasks in biology:
Advice: Read the wording of the questions carefully.
Advice: express your thoughts in a literary way, answer the question in detail and comprehensively, give a definition to 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?
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