Preparation and description of micropreparations of cells of various organisms. Topic: “Preparation and description of micropreparations of cells of various organisms. Tasks for monohybrid crossing

Lab #1

"Preparation and description of micropreparations of cells"

Target: learn how to prepare and describe micropreparations using the example of yeasts and molds.

Equipment : microscope, slides and coverslips, distilled water, dissecting needles, pipettes, filter paper.

Methodical instructions:

1. Prepare preparations and study morphology.

Preparation of preparations . For microscopy of yeast, a drop of the culture under study is applied to a clean slide and the drop is smeared over the surface of the slide with a cover slip. Then the coverslip is lowered onto the wetted surface of the glass slide, excess liquid is removed with filter paper.

For microscopy of microscopic fungi, a piece of mycelium is transferred to a drop of water deposited on a glass slide. Top with a cover glass. Excess liquid is removed with pieces of filter paper.

Description of micropreparations . Examine under a microscope and draw: the shape and location of yeast cells, the structure of the mycelium and the reproductive organs of microscopic fungi. Identify differences and similarities in the structure of the cells of yeast and microscopic fungi.

2. Write a progress report:

Specify the lab number, topic, objectives and equipment

Write down methods for preparing micropreparations of yeast and mold, describe micropreparations

Make a conclusion about the work done.

Lab #2

"Comparison of the structure of animal and plant cells"

Target: compare the structure of animal and plant cells, establish similarities and differences

Equipment: onion, iodine solution, pipettes, glass slides, elodea leaf, ready-made micropreparations of animal cells, microscopes, table "Plant and animal cell in the field of view of a light microscope"

Methodical instructions:

1. Separate a piece of the covering skin from the scales of the bulb and place it on a glass slide in a drop of a weak solution of iodine. After staining the preparation (1-2 min). Blot excess iodine with a tissue.

2. On another glass slide, place an elodea leaf in a drop of water. Wipe off excess water with a tissue.

3. Examine both slides under a microscope, fine-tuning the image of one of the cells in each slide.

4. Make a drawing of a plant cell (one) in a notebook with the designations of all its parts visible under a light microscope.

5. Examine the preparation of an animal cell (take ready-made) under a microscope and make a drawing with the designations of all its parts visible under a microscope.

6. Compare the structure of plant and animal cells. Write the conclusions in your notebook, completing the sentences:

similarity.In a plant and animal cell in the field of view of the light

The microscope can be seen:

Difference.In a plant cell, unlike an animal cell, it is also possible to

See:

Lab #3

"Similarities between human embryos and vertebrates as proof of their evolutionary relationship"

Target : introduce embryonic evidence of the evolution of the organic world, identify similarities and differences in vertebrate embryos

Equipment: textbook "General biology", scheme "The similarity of human embryos and vertebrates"

Methodical instructions:

1. Read the text in General Biology, page 101. "Review of the Embryological Evidence for Evolution." Consider the drawing. Identify the similarities between human embryos and other vertebrates at each stage.

2. Write a report:

Specify the lab number, topic, objectives and equipment

Fix the identified similarities and differences of embryos at each stage of development

Formulate and write down the conclusion about the work done, answering the question what do the similarities of the embryos indicate?

Lab #4

"Diagramming of monohybrid and dihybrid crossing"

Target: learn to solve problems for drawing up schemes of monohybrid and dihybrid crossing

Methodical instructions:

Theory. Define the terms: monohybrid crossing, dihybrid crossing; Formulate and write down the three laws of Mendel.

Practice: Solve problems by drawing up crossover schemes.

1. monohybrid cross

Task number 1. In cattle, the gene that determines the black color of the coat dominates the gene that determines the red color. What offspring can be expected from a cross between a homozygous black bull and a red cow?

Task number 5. In humans, the gene for brown eyes dominates over the gene that causes blue eyes. A blue-eyed man, one of whose parents had brown eyes, married a brown-eyed woman whose father had brown eyes and whose mother was blue. What offspring can be expected from this marriage?

2. Dihybrid cross

In dogs, the black color of the coat dominates over the coffee, and the short coat dominates over the long one. Both pairs of genes are on different chromosomes.

1. What percentage of black shorthair puppies can be expected from crossing two individuals who are heterozygous for both traits?

2. The hunter has bought a black short-haired dog and wants to be sure that it does not carry the genes for coffee-colored long-haired dogs. Which phenotype and genotype partner should be selected for crossing in order to check the genotype of the purchased dog?

Conclusion: formulate and write down the meaning of Mendel's laws for genetics.

Lab #5

"Analysis of phenotypic variability"

Target: verify the existence of modification variability by describing and comparing the phenotypes of specific plants.

Equipment: two copies of natural or herbarium samples of cereal plants of the same variety.

Methodical instructions:

Complete the tasks:

Consider two specimens of wheat plants (rye, barley, etc.) of the same variety, draw, compare these plants, find similarities and differences. Record the results of the observation of phenotypes in a comparative table (comparison criteria can be qualitative and quantitative); Identify the traits that have arisen as a result of modification variability and are determined by the genotype. Answer the questions:

A) Define the terms - variability, modification variability, phenotype, genotype.

B) Is it possible to grow the same crop of vegetables in garden plots with different exposures, with the same care? Why?

5. Make a conclusion about the causes of modification variability.

Write a report:

Complete tasks

Formulate and write down the conclusion about the work done

Lab #6

"Adaptation of organisms to the environment"

Target: learn to identify the features of the adaptability of organisms to the environment and establish its relative nature.

Equipment: herbarium plant specimens, houseplants, stuffed or drawings of animals from various habitats.

Progress

1. Determine the habitat of the plant or animal you are considering. Identify the features of its adaptation to the environment. Reveal the relative nature of fitness. Enter the data obtained in the table "The fitness of organisms and its relativity."

Fitness of organisms and its relativity

Name kind	Habitat	Features adaptability to the environment	What is expressedrelativity fitness

2. After studying all the proposed organisms and filling in the table, based on knowledge of the driving forces of evolution, explain the mechanism for the emergence of adaptations and write down the general conclusion.

Lab #7

"Analysis of hypotheses of the origin of life"

Target : to get acquainted and analyze various hypotheses of the origin of life on Earth.

Methodical instructions:

Read the text "The variety of theories of the origin of life on Earth." Fill in the table:

Theories and hypotheses	Essence of a theory or hypothesis	Proof

3. Formulate and write down the conclusion by answering the question: “What theory do you personally adhere to? Why?"

"A variety of theories of the origin of life on Earth".

1. Creationism.

According to this theory, life arose as a result of some supernatural event in the past. It is followed by followers of almost all the most common religious teachings.

The traditional Judeo-Christian idea of ​​the creation of the world, set forth in the Book of Genesis, has caused and continues to cause controversy. While all Christians acknowledge that the Bible is God's commandment to mankind, there is disagreement about the length of the "day" mentioned in Genesis.

Some believe that the world and all the organisms inhabiting it were created in 6 days of 24 hours. Other Christians do not treat the Bible as a scientific book and believe that the Book of Genesis presents in a form understandable to people the theological revelation about the creation of all living beings by an almighty Creator.

The process of the divine creation of the world is conceived as having taken place only once and therefore inaccessible to observation. This is enough to take the whole concept of divine creation out of the scope of scientific research. Science deals only with those phenomena that can be observed, and therefore it will never be able to either prove or disprove this concept.

2. Theory of a stationary state.

According to this theory, the Earth never came into being, but existed forever; it is always able to maintain life, and if it has changed, then very little; species have always existed.

Modern dating methods give increasingly higher estimates of the age of the Earth, which allows steady state theorists to believe that the Earth and species have always existed. Each species has two possibilities - either a change in numbers or extinction.

Proponents of this theory do not recognize that the presence or absence of certain fossil remains may indicate the time of appearance or extinction of a particular species, and cite as an example a representative of the cross-finned fish - coelacanth. According to paleontological data, the crossopterygians became extinct about 70 million years ago. However, this conclusion had to be revised when living representatives of the crossopterygians were found in the Madagascar region. Proponents of the steady state theory argue that only by studying the living species and comparing them with fossil remains, one can conclude about extinction, and even then it may turn out to be wrong. The sudden appearance of a fossil species in a particular stratum is due to an increase in its population or movement to places favorable for the preservation of remains.

3. Theory of panspermia.

This theory does not offer any mechanism to explain the primary origin of life, but puts forward the idea of ​​its extraterrestrial origin. Therefore, it cannot be considered a theory of the origin of life as such; it simply takes the problem somewhere else in the universe. The hypothesis was put forward by J. Liebig and G. Richter in the middle XIX century.

According to the panspermia hypothesis, life exists forever and is transported from planet to planet by meteorites. The simplest organisms or their spores (“seeds of life”), getting to a new planet and finding favorable conditions here, multiply, giving rise to evolution from the simplest forms to complex ones. It is possible that life on Earth originated from a single colony of microorganisms abandoned from space.

This theory is based on multiple sightings of UFOs, rock carvings of things that look like rockets and "astronauts", and reports of alleged encounters with aliens. When studying the materials of meteorites and comets, many "precursors of life" were found in them - substances such as cyanogens, hydrocyanic acid and organic compounds, which, possibly, played the role of "seeds" that fell on the bare Earth.

Supporters of this hypothesis were Nobel Prize winners F. Crick, L. Orgel. F. Crick relied on two circumstantial evidence:

Universality of the genetic code;

The need for the normal metabolism of all living beings of molybdenum, which is now extremely rare on the planet.

But if life did not originate on Earth, then how did it originate outside of it?

4. Physical hypotheses.

IN The basis of physical hypotheses is the recognition of fundamental differences between living matter and non-living matter. Consider the hypothesis of the origin of life, put forward in the 30s XX century.

Views on the essence of life led Vernadsky to the conclusion that it appeared on Earth in the form of a biosphere. The fundamental, fundamental features of living matter require for its occurrence not chemical, but physical processes. It must be a kind of catastrophe, a shock to the very foundations of the universe.

In line with common in the 30s XX centuries by hypotheses of the formation of the Moon as a result of the separation from the Earth of the substance that previously filled the Pacific Trench, Vernadsky suggested that this process could cause that spiral, vortex movement of the terrestrial substance, which did not happen again.

Vernadsky comprehended the origin of life on the same scale and time intervals as the origin of the Universe itself. In a catastrophe, conditions suddenly change, and living and non-living matter arise from protomatter.

5. Chemical hypotheses.

This group of hypotheses is based on the chemical characteristics of life and links its origin with the history of the Earth. Let's consider some hypotheses of this group.

At the origins of the history of chemical hypotheses were views of E. Haeckel. Haeckel believed that carbon compounds first appeared under the influence of chemical and physical causes. These substances were not solutions, but suspensions of small lumps. Primary lumps were capable of accumulation of various substances and growth, followed by division. Then a nuclear-free cell appeared - the original form for all living beings on Earth.

A certain stage in the development of chemical hypotheses of abiogenesis was concept, put forward by him in 1922-1924. XX century. Oparin's hypothesis is a synthesis of Darwinism with biochemistry. According to Oparin, heredity was the result of selection. In Oparin's hypothesis, what is desired will pass for reality. At first, the features of life are reduced to metabolism, and then its modeling is declared to have solved the riddle of the origin of life.

Hypothesis of J. Burpap suggests that abiogenically arisen small molecules of nucleic acids of a few nucleotides could immediately combine with the amino acids they encode. In this hypothesis, the primary living system is seen as biochemical life without organisms, carrying out self-reproduction and metabolism. Organisms, according to J. Bernal, appear a second time, in the course of the isolation of individual sections of such biochemical life with the help of membranes.

As the last chemical hypothesis for the origin of life on our planet, consider hypothesis put forward in 1988. According to this hypothesis, the origin of organic substances is transferred to outer space. In the specific conditions of space, organic substances are synthesized (numerous orpanic substances are found in meteorites - carbohydrates, hydrocarbons, nitrogenous bases, amino acids, fatty acids, etc.). It is possible that nucleotides and even DNA molecules could have been formed in space. However, according to Voitkevich, chemical evolution on most planets of the solar system turned out to be frozen and continued only on Earth, finding suitable conditions there. During the cooling and condensation of the gaseous nebula, the entire set of organic compounds turned out to be on the primary Earth. Under these conditions, living matter appeared and condensed around the abiogenically formed DNA molecules. So, according to Voitkevich's hypothesis, biochemical life initially appeared, and in the course of its evolution separate organisms appeared.

Lab #8

"Anthropogenic changes in the natural landscapes of their area"

Target: study the environmental problems of the Tula region and identify measures to improve them.

Equipment : manual, map of chemical anthropogenic pollution of the environment.

Methodical instructions:

1. Read the text.

Regional environmental problems of the region are primarily due to the fact that a large number of enterprises of mechanical engineering, chemical and metallurgical industries, several powerful thermal power plants are concentrated on its relatively small territory.

Among all the regions of the center of Russia, the Tula region in terms of the concentration of industrial and energy enterprises per 1 m 2 the area is second only to Moscow. Three cities - Tula, Novomoskovsk and Shchekino - confidently lead the mournful line of 99 Russian cities with unfavorable environmental conditions.

Emissions from enterprises in neighboring regions, especially Moscow, have a great influence on the environmental situation in the Tula region. To this it must be added that the regions of Eastern Europe (including the Tula region) receive up to 40% of atmospheric pollution from Western Europe. The ecological situation in the region has become extremely aggravated as a result of radiation contamination of its territory after the accident at the Chernobyl nuclear power plant.

atmospheric air . Clean air is already becoming a scarce resource in many industrial regions of Russia, where air pollution poses a real danger to human life and health.

Emissions of harmful substances into the atmosphere per 1 km 2 Tula region surpasses Moscow region by 1.7 times, and Kaluga and Oryol regions by more than 10 times. In 2000, about 182 kg of harmful substances emitted into the atmosphere accounted for one inhabitant of the region.

Atmospheric air pollution in terms of the specifics and amount of emissions varies significantly across the regions of the region. The largest number of industrial enterprises, producing about 94% of all emissions, is located in Aleksinsky, Suvorovsky, Efremovsky, Novomoskovsky, Uzlovsky, Shchekinsky districts and in the city of Tula.

One of the main sources of environmental pollution is road transport. In 1999, emissions of pollutants from road transport amounted to 155.1 thousand tons (40% of the mass of all emissions).
Water resources. The main consumer of water in the Tula region is industry (74%); the population consumes 23% of water and agriculture - 3%.

The main users of water resources in the region are the enterprises of Tula and Novomoskovsk. In total, 880 water users of the Tula region were registered in 1999; they consumed about 473 million m3 from natural sources 2 water. At the same time, 280.4 million m 2 , including polluted -259.5; and standard-clean and standard-clean - only 20.9 million m3 2 . Of all the treatment facilities in the region, only 10% operate in the design mode

Despite reduced production, surface waters are heavily polluted. Pollution by industrial and domestic wastes of the rivers Voronka, Shat, Upa, Tulitsa, Myshega, Beshka, Sezha, the upper reaches of the Don has reached such an extent that their self-healing is almost out of the question. In many of them, the maximum permissible concentrations (MPC) for copper and nickel are exceeded by 10-50 times, for lithium and nickel - by 5-10 times, for thallium and mercury - by 2 times.

Groundwater is a natural source of regional drinking and industrial water supply. In the Tula region, 77 deposits of fresh groundwater have been explored, and 40 deposits have been in operation since 1999.

The population of the region is provided only with underground water. River water in settlements is not used for drinking purposes. Groundwater consumption in the region is 1,250 thousand m3 per day. On average, one Tula per day accounts for 300-350 liters of water.

Soils.To protect the soil means to preserve its fertility. The Tula region is an old agricultural region. The main category of the region's land fund is agricultural land - about 1,845 thousand hectares, or 71.8% of its total territory. These lands are mainly used by agricultural enterprises, organizations and citizens engaged in the production of marketable agricultural products.

One of the negative processes for the soils of the region is erosion. Its manifestation largely depends on the degree and nature of economic development and land use. As a result of human activities and geological processes (mainly water activity), currently in the Tula region, about 43% of the total area of ​​agricultural land is subject to intense erosion /

As a result of open mining of minerals, huge areas of fertile land are withdrawn from agricultural circulation. A special place in the conservation of the region's land resources is occupied by reclamation, i.e., the restoration of fields under mine workings.

Exogenous geological processes are quite widely manifested on the territory of the region. The dissolution of limestone layers causes karst disturbances in the relief. Large landslides are observed in the valleys of the Oka, Upa and Besputa rivers, in the ravines and gullies of the Aleksinsky, Yasnogorsky, Leninsky and Shchekinsky regions. Cases of soil subsidence in the locations of old coal mines have become more frequent.

As a result of the accident at the Chernobyl nuclear power plant in 1986, 18 districts of the region were exposed to radioactive contamination, with an area of ​​14.5 thousand km2, which is more than half (56.3%) of its territory. Plavsky, Uzlovsky, Arsenyevsky and Novomoskovsky districts were especially affected. Soils are contaminated with radionuclides: cesium-137 and (to a lesser extent) strontium-90. Currently, there is a trend towards a decrease in the level of the gamma background due to the natural decay of radionuclides and their redistribution in the external environment with the help of water and wind.
Recent studies have shown that about a third of the area of ​​the Tula region is characterized by a high level of soil degradation, close to catastrophic.

Population . Demographic situation. The living conditions of people in the region leave much to be desired. The high population density, the saturation of the region with harmful industries, the severe consequences of radioactive contamination as a result of the Chernobyl accident explain the low level of people's health in comparison with neighboring regions.

One of the main indicators of the state of society is the dynamics of the population. Under favorable conditions, the number increases, under unfavorable conditions, it decreases.

The number of permanent residents of the region is decreasing every year. For the period from 1995 to 2000. this reduction amounted to more than 65 thousand people, or 3.6%. This happened due to an increase in mortality (general and infant), as well as a decrease in the birth rate of the population. The death rate is three times higher than the birth rate.
Currently, diseases of the circulatory system (heart attacks, strokes, hypertension) and respiratory organs are in the first place among the causes of death. They are followed by innovations. These classes of diseases largely depend on the nature of nutrition and the state of the environment. Tuberculosis is the leading cause of death (over 90%) of all infectious diseases controlled in the region.

In 1986, the ecological situation in the region deteriorated sharply as a result of the accident at the Chernobyl nuclear power plant, when more than 50% of the territory of the Tula region was in the zone of radioactive contamination. In this regard, among the population of the affected areas, environmentally dependent diseases (diseases of the upper respiratory tract, gastrointestinal tract, endocrine system), immunity disorders, psychological disorders, diseases of the circulatory system, malignant neoplasms, etc., are becoming more widespread.

According to experts, the Chernobyl "trace" will stretch for at least 70 years and lead to an increase in leukemia, cancer and an increase in infertility in people of reproductive age.

One of the major problems in the area is groundwater pollution . Passing through untreated waste, water forms a toxic filtrate, which includes the remains of decaying organic matter, various dyes, detergents, salts of heavy metals: iron, mercury, lead, etc.

Studies have shown that the high content of iron in Tula water, its increased hardness and the presence of salts of heavy metals are the causes of disorders in the functioning of the kidneys, liver, and thyroid gland. Poor water quality increases the risk of heart attacks, inhibits the reproductive function of the body.

In the region, there is a connection between the increased content of manganese in the atmosphere and the growth of mental disorders. The high concentration of phenol in the atmosphere clearly correlates with the incidence of pharyngitis and bronchitis among children.

With the growth of the car park, the volume of emissions into the atmosphere is constantly growing, amounting in 1999 to 40% of the mass of all harmful emissions into the atmosphere. Dangerous for public health component of emissions from vehicles is not only lead, carbon and nitrogen oxides, hydrocarbons, but also benzapyrene, which is a strong carcinogen.

In the region, the risk of various pathologies in school-age children is sharply increasing. So, while studying at school, children's vision worsens by 3.5 times, the incidence of the digestive tract increases by 5 times, and the incidence of the musculoskeletal system by 8-9 times. Already in the primary grades, 40% of children show signs of neurological diseases, more and more children suffer from mental disorders.

Recent studies have shown that, despite the high tension of the environmental situation in the Tula region, it can be stabilized and then improved by increasing the cost of environmental protection measures. A lot of work in this regard is being carried out by the regional administration together with the committee of natural resources of the Tula region.

2. Answer the questions:

1. What causes the difficult environmental situation in the Tula region?

2. What is the ecological situation in your area, area?

3. What enterprises influence the ecological situation in the region?

4. What industries are degrading the environment in the area where you live?

5. The air of which areas of the region is in the most polluted state?

6. What is the "contribution" of road transport to the air pollution in the region?

7. What is the main source of water in the Tula region?

8. What areas of the region are located in the zones of catastrophic, extremely high and high levels of anthropogenic chemical pollution?

9. What areas of the Tula region were exposed to radioactive contamination as a result of the accident at the Chernobyl nuclear power plant to the greatest extent?

10. What is the demographic situation in the Tula region?

11. How did radioactive contamination of the territory of the region affect people's health?

Write a report:

Specify the lab number, topic, objectives and equipment

Give written answers to questions

Formulate and write down a general conclusion about the environmental situation in the Tula region

Lab #9

"Creating an artificial ecosystem"

Target : using the example of an artificial ecosystem to trace the changes that occur under the influence of environmental conditions.

Methodical instructions:

Complete the tasks and answer the questions:

1. What conditions must be observed when creating an aquarium ecosystem?

2. Draw the aquarium of your dreams.

3. Describe the aquarium as an ecosystem, indicating abiotic, biotic environmental factors, ecosystem components (producers, consumers, decomposers).

4. Make food chains in the aquarium.

5. What changes can occur in the aquarium if:

Falling direct sunlight;

There are a lot of fish in the aquarium.

Write a report:

Specify the lab number, topic, objectives and equipment

Complete tasks

Formulate and record a conclusion about the consequences of changes in ecosystems

1) Temporary preparations

To study plant objects using a light microscope, it is necessary to prepare a micropreparation. Micropreparations not intended for long-term storage are called temporary. The object under study is placed on a glass slide in a drop of water, glycerin, solution, reagent or dye and covered with a cover slip. Such preparations can be stored for several days by placing them in a humid atmosphere.

2) Permanent preparations

Permanent preparations are prepared according to special methods that ensure their storage for decades. Permanent preparations include smears, total preparations and sections. Smears are used in the study of blood cells, cultures of microorganisms, isolated tissue cells. Total preparations are separate transparent and thin objects. Training sections can be made manually using a razor. However, high-quality sections with a given thickness of 10 ... 22 micrometers are usually made using special devices - microtomes. Such sections are often referred to as microtome preparations. To obtain thinner sections (0.01 ... 0.05 microns, or 10 ... 50 nanometers), ultramicrotomes are used.

Let us briefly consider the main steps in the preparation of permanent preparations.

1. Material fixation. Immediately after the end of fixation, the material is washed with either water (after water fixatives), or 80% alcohol (after alcohol fixatives). The number of changes of flushing fluids - at least 3. Time - up to 24 hours.

2. Dehydration in alcohols of increasing concentration. In parallel, the material is compacted. The successive movement of material through a series of solutions is called wiring. After water fixatives, 8 alcohol changes are used: 20%, 40%, 80%, two changes of 96%, two changes of 100%. After alcohol fixatives - 4 alcohol changes: two changes of 96% and two changes of 100%. In each shift, the material is aged for 1 hour.

3. Enlightenment. This is the impregnation of the material with a paraffin solvent - xylene (benzene, chloroform). The sample is placed for 1 hour sequentially in each of the following solutions: 3 parts alcohol + 1 part xylene, then 2 parts alcohol + 2 parts xylene, then 1 part alcohol + 3 parts xylene, then two changes of xylene.

4. Embedded in paraffin. This is the replacement of xylene with paraffin. The sample is placed in a mixture of xylene and paraffin at a temperature of 55 ... 57 degrees and left in a thermostat at this temperature until the xylene has completely evaporated (from several hours to several days). Then, at a temperature of 55 ... 57 degrees, wiring is carried out through paraffin I (6 ... 12 hours), paraffin II (6 ... 12 hours) and pouring into paraffin III. Paraffins I, II, III differ only in purity: paraffin III is the final medium, which must have the highest purity. As a result, paraffin blocks are obtained, in which material samples are enclosed. These blocks can be cut in any direction.

5. Staining of cuts. Paraffin sections are glued to a clean glass slide. As an adhesive, you can use a mixture of chicken egg protein with glycerin (in a ratio of 1: 2) with the addition of an antiseptic (thymol or phenol). Sections are usually deparaffinized. To do this, glass with glued sections is passed through xylene, alcohols of decreasing concentration (100%, 96%, 80%, 70%) and distilled water. The residence time in each medium is 2...3 minutes. Then stained according to the methods.

6. Dehydration and clearing of stained sections. It is carried out by wiring through alcohols of increasing concentration, and then through xylene.

7. Conclusion in the environment (fill). For long-term storage of drugs, they must be enclosed in an environment that protects the drug from air oxidation and fungal attack. For filling, special resins are used (Canadian balsam, fir balsam), which are dissolved in xylene to the consistency of liquid honey. A drop of this solution is applied to the section and covered with a coverslip.

6. Chemical composition of the cellular substance. Micro and macro elements.

More than 80 chemical elements were found in the composition of the cell, while no special elements characteristic only of living organisms were found. However, only 27 elements know what functions they perform. the remaining 53 elements probably enter the body from the external environment.

1. Macronutrients

They make up the bulk of the substance of the cell. They account for about 99% of the mass of the entire cell. The concentration of four elements is especially high: oxygen (65-75%), carbon (15-18%), nitrogen (1.5-3%) and hydrogen (8-10%). Macroelements also include elements whose content in a cell is calculated in tenths and hundredths of a percent. These are, for example, potassium, magnesium, phosphorus, sulfur, iron, chlorine, sodium.

2. Trace elements These include mainly metal atoms that are part of enzymes, hormones and

other vital substances. In the body, these elements are contained in very small quantities: from 0.001 to 0.000001%; among such elements are boron, cobalt, copper, molybdenum, zinc, iodine, bromine, etc.

3. Ultramicroelements

Their concentration does not exceed 0.000001%. These include uranium, radium, gold, mercury, beryllium, cesium and other rare elements. The physiological role of most of these elements in the organisms of plants, animals, fungi and bacteria has not yet been established.

But it is more interesting to observe and study what we already have at hand in a private house, in an apartment and in the yard. The study of what surrounds us every day gives a truly vivid impression. Therefore, take care of the available means of observation and objects.

What does home microscopy usually examine?

The simplest options:

• plants - leaves, stems, roots;
• vegetables, fruits, berries;
• insects;
• microorganisms;
• crystals.

Plants and their fruits

At home, you can start studying the microworld with an ordinary onion, or rather, with its peel. Its structure is thin and is clearly visible even under. But the skin must be tinted with iodine in advance. Sometimes you can get by with greenery. We recommend using special bottles or watch glasses.

Bow research

• Prepare the microscope, adjust the light. Wipe the slide and coverslip with tissue paper. Drop a weak solution of iodine and water onto a glass slide.
• Cut the onion, remove the scales. Tear off a piece of film from the fleshy part of the bulb with tweezers and place it in the created drop on the glass.
• Spread the cooked skin on the glass.
• Cover the specimen with a cover slip.
• Your temporary remedy is ready!
• Observe the slide at 64x magnification (x4 objective, x16 eyepiece). Move the glass slide until you find a suitable spot where the elongated cells are best seen.
• Magnify up to 400x (objective 40x, eyepiece 10x).

A large magnification allows you to consider a dense transparent shell with thinner areas - pores. Inside the cell is a colorless viscous substance - the cytoplasm, stained with iodine. In the cytoplasm you will notice a small dense nucleus where the nucleolus is located. In most cells, especially in old ones, cavities - vacuoles - are clearly distinguishable.

Rice. Photos taken with a microscope

Under a microscope, you will see clearly distinguishable cell nuclei in the structure of the peel. Of course, most adults have already done such an experiment at school, but for the youngest researchers, such an analysis of a plant will be new.

The peel of fruits and berries is also suitable for examination under a microscope. However, the cellular structure of such preparations for research may be indistinguishable, especially when using low-power devices. Plus, it will take a lot of effort and many attempts before you get the perfect drug. Try, for example, cutting the skin off a plum several times until a suitable multicellular layer comes out. Or go through several varieties of grapes at once (fortunately, today you can even buy several berries of different plants in hypermarkets) until you find one in which the coloring substances of the peel have an interesting shape.

Next, move on to potato tubers, which also need to be stained with iodine according to the procedure described above. But before that, cut the potatoes into thin slices. Further, due to the reaction with iodine, layers of blue starch will appear on the potatoes.

But the most accessible plants for research are like leaves, grass or green algae (you can find them in any open water bodies). To see the chloroplasts, make the sections exceptionally thin.

Chloroplasts are green plastids found in photosynthetic eukaryotic cells. Photosynthesis occurs with their help.

Insects and representatives of aquatic fauna

Tired of looking at plants? Move on to flying and crawling creatures. You don't even have to leave your apartment. On the balcony and under the mosquito nets of ordinary windows, as well as on the windshield of the car, a lot of insects gather, including those that have already died. These are all valuable material for your research. On the wings of insects you will see hairs that protect insects from getting wet. The surface tension of a drop of water prevents it from touching the wings. Take a closer look!

Do you remember how you used to catch butterflies as a child? Have you ever wondered what kind of dust falls from her wings?! These are microscopic scales of various shapes, which we, like titans, tear off with a careless touch of our fingers. If you suddenly catch a moth, then use it instead of a butterfly.

Then take a closer look at the limbs of insects and spiders, study the chitinous structure of the cockroach's back film. You will be surprised, but a large magnification of the microscope will help here to see the fused scales that make up such films.

Naturally, not everyone is interested in looking at cockroaches, so just go outside, where it is easier to catch an outlandish insect. Also look into the nearest body of water, where you will definitely find fry of snails, amoebas, daphnia (planktonic crustaceans), slippers and cyclops. The tiny and optically transparent baby snail is best suited for studying the heartbeat.

Consider an example of a study under a microscope of the simplest living organisms (from any outdoor reservoir or home aquarium), which consist of only one cell:

• Take a glass slide with a well from the set of glasses. Clean and degrease it by boiling it in a weak soda solution (a teaspoon per liter of water), and then dry it to dryness.
• Lay a few fibers of cotton wool in the hole. This will slow down the researched protozoa.
• Pipette water onto a glass slide.
• Lubricate the edges of the coverslip with paraffin or petroleum jelly (to prevent evaporation of moisture) and cover the well of the main slide with it.

It is possible to conduct an experiment using ordinary glasses without a recess - a study in a “crushed” drop. In order not to deform the object, draw the edges of the upper glass over the beeswax, thus forming “legs”. Place the thinnest layer of cotton wool or filter paper in the center of the bottom glass. Close the preparation so that air does not get under the upper glass: we bring the lower edge of the coverslip at an angle and lower it gently. In both cases, a sealed chamber should be formed in which the test liquid does not dry out for a long time.

Remember to color slides for better observation. The best vital dye without toxic action is neutral red in a concentration of not more than 1 to 200,000. Good results are obtained by a weak alkaline solution of Congo red. Reagents allow you to study the protozoa in detail, without disturbing their rhythm of life.

Lighting is important too! To study living organisms in finished preparations, slightly darken the field of view. In bright transmitted light, important aspects of the structure of the protozoan are almost indistinguishable. Work with a magnifying device should be started by setting a low magnification with a narrowed aperture. Then gradually increase the picture by turning the revolver with lenses and adjusting the focusing mechanism.

As a result, stock up on jars and bags for any outing into nature. You can collect water from a reservoir in a jar, and put plucked plants and dried remains of insects into a bag. Be careful, remembering that animals and their remains can carry various diseases. Wear gloves, wash your hands and follow other basic hygiene rules.

Microscope.

In this article I will tell you 3 ways to prepare preparations for a microscope. These methods are the simplest.

At the beginning of the article - the so-called dictionary, or rather explanations of what this or that object is.

For the manufacture of micropreparations, a special tool, dyes, as well as a certain accuracy and skill are required. Strict observance of all necessary conditions is very important - otherwise the micropreparation may be unsuitable for research.

On sale there are ready-made sets of preparations for research (which is convenient for home and school) - for example, 25 preparations, or 38 slides from Leeuwenhoek. As well as minerals and other sets.

See the CATALOG of microscopes.

explanations

Fixed drug- in microbiology, fixed preparations are often prepared, so you should know what they are. These preparations are examined under a microscope in a stained form. The word "fixation" means such processing of a living object (which you are going to consider), which makes it possible to quickly interrupt the life processes in a particular object (I will explain more simply - to kill), while maintaining a fine structure. As a result of fixation, the cells are firmly attached to the glass and stain better. Fixation is necessary in case of work with pathogenic microorganisms (for self-safety purposes).

Suspension- a mixture of any substances, where the solid substance is distributed in the form of tiny particles in a liquid substance in a non-settled state.

biological loop- a thin metal stick, at the end - a thin metal loop. It is used to capture a small amount of a particular suspension of microorganisms.

Petrolatum- ointment-like liquid, odorless and tasteless. The mixture consists of mineral oil and solid paraffins (wax-like mixture).

Sealing- ensuring perfect impermeability for various gases and liquids of surfaces and joints of parts.

agar agar- in microbiology, it is used for the manufacture of solid and semi-liquid nutrient media, that is, agar media.

Carnoy's fluid- liquid for fixing.

Burner- a device having an injector, which is installed in a metal tube with holes for atmospheric air to enter this tube, which is fixed on a stand with a side inlet for supplying gas to the tube, while the holes are made on the side surface of the tube, on which to change the air supply to burner, a movable damper can be installed that changes the flow area of ​​these holes.

Nikiforov's mixture- a mixture of equal volumes of ethyl alcohol and anhydrous sulfuric ether, used to fix blood smears, smears-prints of organs and any tissues.

Preparation of the drug "crushed drop"

Preparation of the drug "hanging drop"

Hanging drop.

1. Gently place one drop of microorganism suspension (prepared) using a biological loop on a clean coverslip.
2. Invert the cover slip containing the suspension drop so that the drop hangs freely.
3. Place an inverted cover slip with a drop over the well of a special coverslip with a depression in the center.
4. The drop should not touch the edges of the glass and the recess (hole), it should hang freely on the coverslip.
5. The edges of the recess of a special cover glass are preliminarily lubricated with Vaseline to seal the chamber.
6. Enjoy observing bacteria in a micropreparation!

Preparation of the drug "imprint"

From an agar medium on which some microorganisms grow in an absolute continuous lawn or in the form of individual colonies, carefully cut out a not very large cube with a scalpel.

Transfer it to a glass slide so that the surface of the microorganism cube is facing up.

Then, apply an ordinary coverslip (absolutely clean) to the lawn of microorganisms or to the colony, gently and not strongly, but lightly, press on it with a biological loop or tweezers and immediately remove it, trying not to move it to the side.

The resulting preparation (a cover slip with an imprint) is placed with the imprint down in a drop of ordinary water on a clean glass slide. An imprint can also be obtained on a glass slide by touching the surface of the colony with the glass slide.

1. The drug is ready!
2. Attention! Living cell preparations are examined using a "dry systems" microscope. After microscopy, such preparations must be kept in a disinfectant solution (disinfectant) before washing.

Preparation of the "imprint" preparation, another method

Preparation of the "fixed smear" preparation

In order to prepare this preparation, one drop of water is required on a defatted glass slide.

Introduce the material you are studying with a biological loop into it and distribute it so as to obtain a thin and uniform smear with a diameter of about 1-1.5 centimeters (only with such a distribution of the material in the smear can you see isolated bacterial cells).

If the test material is contained in a liquid medium, then it is directly applied to a glass slide with a loop and a smear is prepared. The smears are dried in air or in a stream of warm air over a burner flame.


To fix the smear, the glass slide (namely, with the smear up) is very carefully and slowly passed 3 times (within 3 seconds) through the burner flame. The microorganisms in the smear die during fixation, tightly attaching to the surface of the glass slide, and they are not washed off during further processing of the preparation.

1. Ready!

Attention! Longer heating can cause deformation of cell structures. Blood smears, smears-prints of organs and any tissues and (in some cases, smears from cultures) are fixed by immersion for 5-20 minutes in methyl blue or ethyl alcohol, Nikiforov's mixture, also sublimate alcohol or other fixing liquids.

Examples of microscope slides

List of slides of the 25-slide set from WSBD World:

Loose Connective Tissue
Spinal Cord c.s. Cross section of the spinal cord
Motor Nerve Ending
Stomach Mammal Sec. Section of mammalian stomach tissue
Kidney c.s. Cross section of a kidney
Artery & Vein c.s. Cross section of a vein and artery
Blood Vessel of Lung
Blood Vessel of kidney
Tase Bud Taste Bud
Mouth Smear
Human Sperm Smear
Mitosis of Animal Cell
Hydra thru Testis c.s. Hydra testis
Hydra thru Ovary c.s. Hydra ovary
Hydra with Bud
Fern Prothalium wm Fern growth
Zea Mays Seed l.s. Cut of corn seeds
Spirogyra Spirogyra
Lung Mammal Mammal lung
Colon Mammal Mammal colon
Trachea Mammal
Pancreas Mammal
Uterus Mammal
Spleen Mammal
Onion Root Tips

Contents of another kit (38 pcs) - Levenhuk N38 NG ready-made slides set:

Botany and zoology:

onion peel
Grain of rye
root cap
linden branch
Anther
Ovary
Camellia
Geranium leaf epidermis
bee limb
bee wing
Cyclops
Volvox
Euglena
Infusoria shoe
Earthworm (cross section)
mosquito mouthparts
Ascaris
Daphnia

Biology and Physiology:

Drosophila mutation (wingless form)
Drosophila mutation (black body)
Drosophila "norm"
animal cell
plant cell
Mold mukor
Cleavage of the egg
Mitosis in an onion root
striated muscles
mammalian spermatozoa
Nerve (cross section)
Loose connective tissue
mammalian egg
Nerve cells
hyaline cartilage
Smooth muscles
Bone
frog blood
human blood
Single layer epithelium

State budget educational institution

Higher professional education

"Bashkir State Medical University"

Ministry of Health and Social Development

Russian Federation

Department of Pharmacognosy with a course of botany and the basics of herbal medicine

"9" _ September _____2012

Discipline Botany Speciality 060301 Pharmacy

Well 1 (full-time department) Semester 1

Section: “The doctrine of the cell. Ergastic and secretory substances in the plant cell

Lab #1

Presentation on theme: "Optical microscopes. Features of botanical microtechnology. Osmotic properties of the plant cell

Lab #2

Presentation on theme: "The structure of the cell wall. Plastids, spare and mineral inclusions"

students

Ufa 2012
Lab #1

Topic of the lesson: “Optical microscopes. Features of botanical microtechnology. Osmotic properties of the plant cell

1. Relevance. The study of methods of botanical microtechnics is a prerequisite for mastering practical skills in the section "Cytology, histology and anatomy of plants." The study of the structure of a plant cell and its osmotic properties gives an idea of ​​the cellular organization of plant organisms, structural features and differences from animals.

2. Objectives of the lesson:

1. Acquire the skills of working with a microscope;

2. Acquire the skills of preparing temporary micropreparations

3. Acquire the skills of botanical microtechnology for microscopic analysis of whole, cut and powdered medicinal plant materials;

4. Study the structural features of a plant cell

5. Study the properties of a plant cell

know :

The device of the microscope and the rules for working with it;

· the history of the study of the cell, the postulates of cell theory;

The structure of a prokaryotic cell

The structure of the eukaryotic cell, its main organelles;

Features of the structure of the plant cell.

For the formation of professional competencies, the student must be able to :

prepare a micropreparation;

Examine the micropreparation at low and high magnification of the microscope;

find the organs of the cell;

· carry out the reactions of plasmolysis and deplasmolysis, give a theoretical justification;

For the formation of professional competence, the student must own :

Botanical conceptual apparatus;

· technique of microscopy and histochemical analysis of micropreparations of plant objects.

3. Necessary basic knowledge and skills:

modern ideas about the structure of prokaryotic and eukaryotic cells, their differences.

microscope device.

4. Duration of extracurricular work– 2 academic hours (90 min).

Questions for self-preparation:

1. Microscope. Mechanical and optical systems.

2. Rules for working with a microscope

3. Working distance. Resolution. General increase.

4. Cell. History of study. cell theory

5. The difference between a plant cell and a fungus and animal cell

6. The structure of the cell. Core, structure, functions.

7. Plant cell organelles. Structure, functions

8. Cytoplasm. Structure, functions

9. Vacuole, structure, functions

Explanation for tasks

Microscope.

Microscope - an optical-mechanical system that allows you to get a greatly enlarged image of objects whose dimensions lie far beyond the resolution of the naked eye. The resolution of the eye is 0.15 mm. The resolution of light microscopes is 300-400 times higher than the resolution of the naked eye and is equal to 0.1-0.3 microns.

In a microscope, optical and mechanical systems are distinguished. The optical system consists of an illuminator, a lens and an eyepiece. The mechanical system consists of a revolver, a tube, a tripod, an object table, macro and micro screws.

The lighting apparatus includes:

Condenser (designed for the best lighting, image sharpness control);

Iris diaphragm (designed to regulate the diameter of the light beam and the depth of the field of view);

Mirror (designed to direct rays from the light source to the condenser).

The lens is the most important part of the optical system. The lens gives an image of the object with the reverse arrangement of parts. At the same time, it reveals (“resolves”) structures that are inaccessible to the naked eye.

The eyepiece is used to observe the image built by the lens. The aperture of the eyepiece defines the boundaries of the field of view. In general, the objective and the eyepiece both provide the resolving power of the microscope and determine the total magnification of the microscope (the total magnification of a microscope is defined as the product of the magnification of the objective eyepiece).

The mechanical system of the microscope is designed to mount parts of the optical system.

Working with a microscope

1. Install the microscope opposite the left shoulder, make room in front of you for the album. Put the lens in working position. The correct installation of the lens should be judged by the click that is felt when the revolver is rotated. The distance between the objective and the slide should be about 1 cm. Always start working with a microscope at a low magnification.

2. Fully open the diaphragm. Raise the condenser to the level of the stage. Aim the light with a concave mirror so that the entire field is illuminated brightly and evenly.

3. Put the prepared micropreparation on the stage so that one of the sections is located exactly under the objective. To fix the micropreparation, press the slide with a clamp.

4. Using the macro screw, set the required focal length to obtain a clear image in the microscope. Correct the distance with a microscrew.

5. Before transferring the microscope to a higher magnification, select the desired cut point, place it in the center of the field of view, and only then change the objectives by carefully rotating the revolver.

6. After finishing work, you need to transfer the microscope to a low magnification and remove the micropreparation.

7. After use, the microscope should be closed with a cap to protect or dust.

Method for preparing temporary micropreparations

1. The object must be taken in the left hand and clamped with three fingers, in the right hand it is necessary to hold a safety razor or blade.

2. Align the surface of the object so that the cut plane is perpendicular to the axis of the organ. Slices are made by moving the razor towards you.

3. Apply 2-3 drops of water to the middle of the slide with a pipette and transfer the thinnest sections at the tip of the dissecting needle, cover the object with a cover slip. Liquid must not leak from under the coverslip.

4. Put the prepared preparation on the object table, examine it at low and high magnifications.

5. In addition to temporary preparations, permanent preparations are used to study objects. The inclusion liquid in them is glycerin with gelatin or Canadian balsam.

6. When staining the drug, it should be taken into account that under the action of concentrated acids, organic inclusions in the cell can be charred, mineral inclusions (crystals, druses, cystoliths) can completely disappear or change their shape.

7. You can not remove the drug from under the x40 lens, because. its working distance is 0.6 mm and it is easy to spoil the front lens.

Cell

The cell is the basic structural and functional unit of all living things. Cells were first described by Robert Hooke in the mid-seventeenth century (1665) while examining a piece of cork. Knowledge of the cell expanded with the improvement of the microscope. By the middle of the nineteenth century, enough knowledge about the cell had been accumulated - the discovery of the nucleus, plastids, cell division, etc. All knowledge about the cell was summarized at the turn of the 30-40s of the 19th century by the botanist M. Schleiden and the zoologist T. Schwann in the form of cell theory.

The main theses (postulates) of the cell theory:

1. cell - a structural and functional unit of all living things;

2. a multicellular organism is a complexly organized, integrated system consisting of functioning and interacting cells;

3. all cells are homologous in structure;

4. "cell from cell." The principle of cell continuity by division was founded in 1958 by the German scientist R. Virchow.

The shape, structure and size of cells are very diverse. The plant cell is made up of protoplast, membrane or cell wall and vacuole.

Protoplast includes: cytoplasm, nucleus, plastids, mitochondria.

Cytoplasm- part of the protoplast between the plasma membrane and the nucleus. The basis of the cytoplasm is its matrix, or hyaloplasm- a complex, colorless colloidal system. The most important role of hyaloplasm is to unite all cellular structures into a single system, ensuring interaction between them in the processes of cellular metabolism. In the cytoplasm, most of the processes of cellular metabolism are carried out, except for the synthesis of nucleic acids.

Core- an obligatory and main part of the living cell of all eukaryotes. Functions of the nucleus: storage and reproduction of hereditary information, control of metabolism and almost all processes occurring in the cell, nucleic acid synthesis, protein synthesis. The nucleus is surrounded by a membrane consisting of two membranes bearing very large pores. The internal contents of the nucleus are called nuclear sap, or nucleoplasm. One or more nucleoli are immersed in the nuclear juice.

Mitochondria cell organelles, the shape, size and number of which are constantly changing. The main function is to provide the energy needs of the cell by oxidizing energy-rich substances (sugars) and synthesizing ATP and ADP. Mitochondria are surrounded by two membranes, the inner one forms outgrowths - cristae. Mitochondria, like plastids, are semi-autonomous organelles, because contain DNA and ribosomes in the matrix.

plastids characteristic only of plants. There are three types of plastids: chloroplasts, chromoplasts and leukoplasts. The main function of chloroplasts is photosynthesis, leukoplasts are the storage of nutrients and chromoplasts are the color of flowers and fruits. Chloroplasts consist of a double membrane, matrix, thylakoids combined into grana, DNA, ribosomes, grains of primary starch.

Golgi complex- a system of discoid sacs and vesicles surrounded by membranes. Performs the functions of synthesis, accumulation and isolation of certain polysaccharides (pectins, mucus, etc.), secondary metabolites; the formation of vacuoles and lysosomes; distribution and intracellular transport of certain proteins; participates in the construction of the cytoplasmic membrane.

EPS (endoplasmic reticulum) - membrane-limited system of submicroscopic channels. EPS is divided into smooth and rough. Rough EPS functions: protein synthesis; directed transport of macromolecules and ions; membrane formation; organelle interaction. The function of smooth EPS is the synthesis of lipophilic compounds.

Vacuole- a cavity in a cell surrounded by a membrane (tonoplast) and filled with cell sap. Cell sap is an aqueous solution of various substances - protoplast waste products. Functions of vacuoles: accumulation of reserve substances and slags; maintenance of cell turgor; regulation of the water-salt balance of the cell.

cell wall separates the cell from the environment. It is based on cellulose molecules, which are grouped into microfibrils and fibrils. Cellulose molecules are immersed in a matrix, which consists of polysaccharides with a more branched structure - hemicelluloses and pectins, as well as water. The cell wall is very strong, and at the same time, elastic. Strength is given to it by cellulose molecules, elasticity - by the matrix. The cell wall performs shaping and mechanical functions, protects the protoplast, resists the high osmotic pressure of the vacuole, and substances are transported through the cell wall.