If we examine the pulp of the fruit of a tomato or watermelon with a microscope magnification of about 56 times, rounded transparent cells are visible. In an apple they are colorless, in a watermelon and a tomato they are pale pink. The cells in the "slurry" lie loosely, separated from each other, and therefore it is clearly visible that each cell has its own shell, or wall.
Conclusion: A living plant cell has:
1. Living contents of the cell. (cytoplasm, vacuoles, nucleus)
2. Various inclusions in the living content of the cell. (deposits of reserve nutrients: protein grains, oil drops, starch grains.)
3. Cell membrane, or wall. (It is transparent, dense, elastic, does not allow the cytoplasm to spread, gives the cell a certain shape.)
Magnifier, microscope, telescope.
Question 2. What are they used for?
They are used to enlarge the object in question several times.
Laboratory work No. 1. The device of a magnifying glass and examining the cellular structure of plants with its help.
1. Consider a hand magnifier. What parts does it have? What is their purpose?
A hand magnifier consists of a handle and a magnifying glass, convex on both sides and inserted into a frame. When working, the magnifying glass is taken by the handle and brought closer to the object at such a distance at which the image of the object through the magnifying glass is the clearest.
2. Examine with the naked eye the pulp of a semi-ripe fruit of a tomato, watermelon, apple. What is characteristic of their structure?
The pulp of the fruit is loose and consists of the smallest grains. These are cells.
It is clearly seen that the pulp of the tomato fruit has a granular structure. In an apple, the flesh is a little juicy, and the cells are small and close to each other. The pulp of a watermelon consists of many cells filled with juice, which are located either closer or further away.
3. Examine the pieces of fruit pulp under a magnifying glass. Sketch what you see in a notebook, sign the drawings. What shape are the fruit pulp cells?
Even with the naked eye, and even better under a magnifying glass, you can see that the pulp of a ripe watermelon consists of very small grains, or grains. These are cells - the smallest "bricks" that make up the bodies of all living organisms. Also, the pulp of a tomato fruit under a magnifying glass consists of cells that look like rounded grains.
Laboratory work No. 2. The device of the microscope and methods of working with it.
1. Examine the microscope. Find the tube, eyepiece, lens, stage stand, mirror, screws. Find out what each part means. Determine how many times the microscope magnifies the image of the object.
The tube is a tube that contains the eyepieces of a microscope. Eyepiece - an element of the optical system facing the eye of the observer, part of the microscope, designed to view the image formed by the mirror. The lens is designed to build an enlarged image with fidelity in terms of the shape and color of the object of study. The tripod holds the tube with the eyepiece and objective at a certain distance from the object table, which is placed on the test material. The mirror, which is located under the object table, serves to supply a beam of light under the object under consideration, i.e., improves the illumination of the object. Microscope screws are mechanisms for adjusting the most efficient image on the eyepiece.
2. Familiarize yourself with the rules for using a microscope.
When working with a microscope, the following rules must be observed:
1. Work with a microscope should be sitting;
2. Inspect the microscope, wipe the lenses, eyepiece, mirror from dust with a soft cloth;
3. Set the microscope in front of you, a little to the left, 2-3 cm from the edge of the table. Do not move it during operation;
4. Fully open the diaphragm;
5. Always start working with a microscope at a low magnification;
6. Lower the lens to the working position, i.e. at a distance of 1 cm from the glass slide;
7. Set the illumination in the field of view of the microscope using a mirror. Looking into the eyepiece with one eye and using a mirror with a concave side, direct the light from the window into the lens, and then maximally and evenly illuminate the field of view;
8. Put the micropreparation on the stage so that the object under study is under the lens. Looking from the side, lower the lens with a macro screw until the distance between the lower lens of the objective and the micropreparation is 4-5 mm;
9. Look into the eyepiece with one eye and turn the coarse adjustment screw towards yourself, smoothly raising the lens to a position at which the image of the object will be clearly visible. You can not look into the eyepiece and lower the lens. The front lens can crush the coverslip and scratch it;
10. Moving the preparation with your hand, find the right place, place it in the center of the microscope field of view;
11. Upon completion of work with a high magnification, set a low magnification, raise the objective, remove the preparation from the working table, wipe all parts of the microscope with a clean cloth, cover it with a plastic bag and put it in a cabinet.
3. Work out the sequence of actions when working with a microscope.
1. Place the microscope with a tripod towards you at a distance of 5-10 cm from the edge of the table. Aim the light with a mirror into the opening of the stage.
2. Place the prepared preparation on the stage and secure the slide with clips.
3. Using the screw, slowly lower the tube so that the lower edge of the lens is 1-2 mm from the preparation.
4. Look into the eyepiece with one eye, without closing or closing the other. While looking into the eyepiece, use the screws to slowly raise the tube until a clear image of the object appears.
5. Put the microscope back in its case after use.
Question 1. What magnifying devices do you know?
Hand magnifier and tripod magnifier, microscope.
Question 2. What is a loupe and what magnification does it give?
A magnifying glass is the simplest magnifying device. A hand magnifier consists of a handle and a magnifying glass, convex on both sides and inserted into a frame. It magnifies objects by 2-20 times.
A tripod magnifier magnifies objects 10-25 times. Two magnifying glasses are inserted into its frame, mounted on a stand - a tripod. An object table with a hole and a mirror is attached to the tripod.
Question 3. How does a microscope work?
Magnifying glasses (lenses) are inserted into the telescope, or tube, of this light microscope. At the top end of the tube is an eyepiece through which various objects are viewed. It consists of a frame and two magnifying glasses. At the lower end of the tube is placed a lens consisting of a frame and several magnifying glasses. The tube is attached to a tripod. An object table is also attached to the tripod, in the center of which there is a hole and a mirror under it. Using a light microscope, one can see an image of an object illuminated with the help of this mirror.
Question 4. How to find out what magnification the microscope gives?
To find out how much the image is magnified when using a microscope, multiply the number on the eyepiece by the number on the objective lens being used. For example, if the eyepiece is 10x and the objective is 20x, then the total magnification is 10 x 20 = 200x.
Think
Why is it impossible to study opaque objects with a light microscope?
The main principle of operation of a light microscope is that light rays pass through a transparent or translucent object (object of study) placed on the object table and enter the lens system of the objective and eyepiece. And light does not pass through opaque objects, respectively, we will not see the image.
Tasks
Learn the rules for working with a microscope (see above).
The light microscope made it possible to examine the structure of cells and tissues of living organisms. And now, it has already been replaced by modern electron microscopes, which allow us to examine molecules and electrons. A scanning electron microscope allows you to obtain images with a resolution measured in nanometers (10-9). It is possible to obtain data concerning the structure of the molecular and electronic composition of the surface layer of the surface under study.
Studying in practice the science of plants, botany and carpology, it is interesting to touch on the topic of the apple tree and its multi-seeded non-opening fruits, which a person has been eating since ancient times. There are many varieties, the most common type is "home". It is from it that manufacturers all over the world make canned food and drinks. Having examined an apple under a microscope, one can note the similarity of the structure with a berry, which has a thin shell and a juicy core and contains multicellular structures - seeds.
The apple is the final stage in the development of the flower of the apple tree, occurring after double fertilization. Formed from the ovary of the pistil. A pericarp (or, pericarp) is formed from it, which performs a protective function and serves for further reproduction. It, in turn, is divided into three layers: exocarp (outer), mesocarp (middle), endocarp (inner).
Analyzing the morphology of apple tissue at the cell level, we can distinguish the main organelles:
- Cytoplasm - a semi-liquid medium of organic and inorganic substances. For example, salts, monosaccharides, carboxylic acids. It combines all components into a single biological mechanism, providing endoplasmic cyclosis.
- Vacuole is an empty space filled with cell sap. It organizes salt metabolism and serves to remove metabolic products.
- The nucleus is the carrier of genetic material. It is surrounded by a membrane.
Observation methods apples under the microscope:
- Transient lighting. The light source is located under the study drug. The microsample itself must be very thin, almost transparent. For these purposes, a slice is prepared according to the technology described below.
Preparation of a micropreparation of apple pulp:
- Make a rectangular incision with a scalpel and carefully remove the skin with tweezers;
- With a medical dissecting needle with a straight tip, transfer a piece of flesh to the center of the glass slide;
- With a pipette, add one drop of water and a dye, for example, a solution of brilliant green;
- Cover with a cover glass;
Microscoping is best started at a low magnification of 40x, gradually increasing the magnification up to 400x (maximum 640x). The results can be recorded in digital form by displaying the image on a computer screen through an eyepiece camera. Usually it is purchased as an optional accessory and is characterized by the number of megapixels. With its help, the photos presented in this article were taken. To take a photo, you need to focus and press the virtual photo button in the program interface. Short videos are made in the same way. The software includes functionality that allows linear and angular measurements of areas of particular interest to the observer.
Even with the naked eye, and even better under a magnifying glass, you can see that the pulp of a ripe watermelon, tomato, apple consists of very small grains, or grains. These are cells - the smallest "bricks" that make up the bodies of all living organisms.
What do we do. Let's make a temporary micropreparation of a tomato fruit.
Wipe the glass slide and coverslip with a paper towel. Pipette a drop of water onto a glass slide (1).
What to do. With a dissecting needle, take a small piece of fruit pulp and place it in a drop of water on a glass slide. Mash the pulp with a dissecting needle until a slurry is obtained (2).
Cover with a cover slip, remove excess water with filter paper (3).
What to do. Examine the temporary micropreparation with a magnifying glass.
What we observe. It is clearly seen that the pulp of the tomato fruit has a granular structure (4).
These are the cells of the pulp of the tomato fruit.
What we do: Examine the micropreparation under a microscope. Find individual cells and examine at low magnification (10x6), and then (5) at high magnification (10x30).
What we observe. The color of the tomato fruit cell has changed.
Changed its color and a drop of water.
Conclusion: The main parts of a plant cell are the cell membrane, the cytoplasm with plastids, the nucleus, and the vacuoles. The presence of plastids in the cell is a characteristic feature of all representatives of the plant kingdom.
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Biology is the science of life, the living organisms that live on Earth.
Biology studies the structure and activity of living organisms, their diversity, the laws of historical and individual development.
The area of distribution of life is a special shell of the Earth - the biosphere.
The branch of biology that deals with the relationship of organisms to each other and to their environment is called ecology.
Biology is closely connected with many aspects of human practical activity - agriculture, medicine, various industries, in particular food and light industries, etc.
Living organisms on our planet are very diverse. Scientists distinguish four kingdoms of living beings: Bacteria, Fungi, Plants and Animals.
Every living organism is made up of cells (viruses are an exception). Living organisms feed, breathe, excrete waste products, grow, develop, multiply, perceive environmental influences and react to them.
Every organism lives in a specific environment. Everything that surrounds a living being is called a habitat.
There are four main habitats on our planet, developed and inhabited by organisms. These are water, ground-air, soil and the environment inside living organisms.
Each environment has its own specific living conditions to which organisms adapt. This explains the great diversity of living organisms on our planet.
Environmental conditions have a certain influence (positive or negative) on the existence and geographical distribution of living beings. In this regard, environmental conditions are considered as environmental factors.
Conventionally, all environmental factors are divided into three main groups - abiotic, biotic and anthropogenic.
Chapter 1
The world of living organisms is very diverse. To understand how they live, that is, how they grow, feed, reproduce, it is necessary to study their structure.
In this chapter you will learn
About the structure of the cell and the vital processes occurring in it;
About the main types of tissues that make up organs;
On the device of a magnifying glass, a microscope and the rules for working with them.
You will learn
Prepare micropreparations;
Use a magnifying glass and a microscope;
Find the main parts of a plant cell on a micropreparation, in the table;
Schematically depict the structure of the cell.
§ 6. The device of magnifying devices
1. What magnifying devices do you know?
2. What are they used for?
If we break a pink, unripe fruit of a tomato (tomato), watermelon or apple with loose pulp, we will see that the pulp of the fruit consists of tiny grains. This cells. They will be better seen if you examine them with magnifying instruments - a magnifying glass or a microscope.
Loupe device. magnifying glass- the simplest magnifying device. Its main part is a magnifying glass, convex on both sides and inserted into the frame. Magnifiers are manual and tripod (Fig. 16).
Rice. 16. Manual magnifier (1) and tripod (2)
hand magnifier increases items by 2-20 times. When working, it is taken by the handle and brought closer to the object at such a distance at which the image of the object is most clear.
tripod magnifier increases items by 10-25 times. Two magnifying glasses are inserted into its frame, mounted on a stand - a tripod. An object table with a hole and a mirror is attached to the tripod.
The device of a magnifying glass and examining with its help the cellular structure of plants
1. Consider a hand magnifier. What parts does it have? What is their purpose?
2. Examine with the naked eye the pulp of a semi-ripe fruit of a tomato, watermelon, apple. What is characteristic of their structure?
3. Examine the pieces of fruit pulp under a magnifying glass. Sketch what you see in a notebook, sign the drawings. What shape are the fruit pulp cells?
Light microscope device. With a magnifying glass, you can see the shape of the cells. To study their structure, they use a microscope (from the Greek words "micros" - small and "scopeo" - I look).
The light microscope (Fig. 17) that you work with at school can magnify the image of objects up to 3600 times. into the telescope, or tube, this microscope has magnifying glasses (lenses) inserted. At the top end of the tube is eyepiece(from the Latin word "oculus" - eye), through which various objects are viewed. It consists of a frame and two magnifying glasses.
At the lower end of the tube is placed lens(from the Latin word "objectum" - an object), consisting of a frame and several magnifying glasses.
The tube is attached to tripod. Also attached to the tripod object table, in the center of which there is a hole and under it mirror. Using a light microscope, one can see an image of an object illuminated with the help of this mirror.
Rice. 17. Light microscope
To find out how much the image is enlarged when using a microscope, you need to multiply the number indicated on the eyepiece by the number indicated on the object used. For example, if the eyepiece is 10x and the objective is 20x, then the total magnification is 10 × 20 = 200 times.
How to work with a microscope
1. Place the microscope with the tripod facing you at a distance of 5–10 cm from the edge of the table. Aim the light with a mirror into the opening of the stage.
2. Place the prepared preparation on the stage and fix the glass slide with clamps.
3. Using the screw, slowly lower the tube so that the lower edge of the objective is 1–2 mm from the preparation.
4. Look into the eyepiece with one eye, without closing or closing the other. While looking into the eyepiece, use the screws to slowly raise the tube until a clear image of the object appears.
5. Put the microscope back in its case after use.
A microscope is a fragile and expensive device: you need to work with it carefully, strictly following the rules.
The device of the microscope and methods of working with it
1. Examine the microscope. Find the tube, eyepiece, lens, stage stand, mirror, screws. Find out what each part means. Determine how many times the microscope magnifies the image of the object.
2. Familiarize yourself with the rules for using a microscope.
3. Work out the sequence of actions when working with a microscope.
CELL. Magnifier. MICROSCOPE: TUBE, EYECOOLER, LENS, STAND
Questions
1. What magnifying devices do you know?
2. What is a loupe and how much magnification does it give?
3. How is a microscope made?
4. How do you know what magnification a microscope gives?
Think
Why is it impossible to study opaque objects with a light microscope?
Tasks
Learn the rules for working with a microscope.
Using additional sources of information, find out what details of the structure of living organisms allow you to see the most modern microscopes.
Do you know that…
Light microscopes with two lenses were invented in the 16th century. In the 17th century Dutchman Anthony van Leeuwenhoek designed a more advanced microscope, giving an increase of up to 270 times, and in the 20th century. The electron microscope was invented, magnifying the image by tens and hundreds of thousands of times.
§ 7. The structure of the cell
1. Why is the microscope you work with called a light microscope?
2. What is the name of the smallest grains that make up the fruits and other plant organs?
You can get acquainted with the structure of the cell using the example of a plant cell, examining a preparation of onion scales under a microscope. The preparation sequence is shown in Figure 18.
On the micropreparation, oblong cells are visible, tightly adjacent to one another (Fig. 19). Each cell has a dense shell With pores which can only be seen at high magnification. The composition of the membranes of plant cells includes a special substance - cellulose, giving them strength (Fig. 20).
Rice. 18. Preparation of the onion peel preparation
Rice. 19. Cellular structure of onion skin
Under the cell wall is a thin film membrane. It is easily permeable to some substances and impermeable to others. The semi-permeability of the membrane is maintained as long as the cell is alive. Thus, the shell maintains the integrity of the cell, gives it a shape, and the membrane regulates the flow of substances from the environment into the cell and from the cell into its environment.
Inside is a colorless viscous substance - cytoplasm(from the Greek words "kitos" - vessel and "plasma" - formation). With strong heating and freezing, it is destroyed, and then the cell dies.
Rice. 20. The structure of a plant cell
The cytoplasm contains a small dense core, in which one can distinguish nucleolus. Using an electron microscope, it was found that the cell nucleus has a very complex structure. This is due to the fact that the nucleus regulates the life processes of the cell and contains hereditary information about the body.
In almost all cells, especially in old ones, cavities are clearly visible - vacuoles(from the Latin word "vacuus" - empty), limited by a membrane. They are filled cell sap- water with sugars and other organic and inorganic substances dissolved in it. When cutting a ripe fruit or other juicy part of a plant, we damage the cells, and juice flows out of their vacuoles. Cell sap may contain dyes ( pigments), giving a blue, purple, crimson color to the petals and other parts of plants, as well as autumn leaves.
Preparation and examination of the preparation of onion scales under a microscope
1. Consider in Figure 18 the sequence of preparation of the onion skin preparation.
2. Prepare the glass slide by carefully wiping it with gauze.
3. Pipette 1-2 drops of water onto a glass slide.
Using a dissecting needle, carefully remove a small piece of transparent skin from the inner surface of the onion scales. Place a piece of skin in a drop of water and flatten with the tip of a needle.
5. Cover the skin with a coverslip as shown.
6. View the prepared preparation at low magnification. Note which parts of the cell you see.
7. Stain the slide with iodine solution. To do this, put a drop of iodine solution on a glass slide. With the filter paper on the other hand, pull off the excess solution.
8. Examine the stained preparation. What changes have taken place?
9. View the specimen at high magnification. Find on it a dark stripe surrounding the cell - a shell; under it is a golden substance - the cytoplasm (it can occupy the entire cell or be near the walls). The nucleus is clearly visible in the cytoplasm. Find a vacuole with cell sap (it differs from the cytoplasm in color).
10. Draw 2-3 onion skin cells. Designate the membrane, cytoplasm, nucleus, vacuole with cell sap.
The cytoplasm of a plant cell contains numerous small bodies. plastids. At high magnification, they are clearly visible. In the cells of different organs, the number of plastids is different.
In plants, plastids can be of different colors: green, yellow or orange and colorless. In cells of the skin of onion scales, for example, plastids are colorless.
The color of certain parts of them depends on the color of plastids and on the dyes contained in the cell sap of various plants. So, the green color of the leaves is determined by plastids called chloroplasts(from the Greek words "chloros" - greenish and "plastos" - fashioned, created) (Fig. 21). Chloroplasts contain a green pigment chlorophyll(from the Greek words "chloros" - greenish and "fillon" - leaf).
Rice. 21. Chloroplasts in leaf cells
Plastids in Elodea leaf cells
1. Prepare a preparation of elodea leaf cells. To do this, separate the leaf from the stem, put it in a drop of water on a glass slide and cover with a coverslip.
2. Examine the specimen under a microscope. Find chloroplasts in cells.
3. Sketch the structure of an elodea leaf cell.
Rice. 22. Forms of plant cells
The color, shape, and size of the cells of different plant organs are very diverse (Fig. 22).
The number of vacuoles in cells, plastids, the thickness of the cell membrane, the location of the internal components of the cell varies greatly and depends on what function the cell performs in the plant body.
ENVELOPE, CYTOPLASMA, NUCLEUS, NUCLEOL, VACUOLES, PLASTIDS, CHLOROPLASTS, PIGMENTS, CHLOROPHYLL
Questions
1. How to prepare an onion skin preparation?
2. What is the structure of a cell?
3. Where is cell sap located and what does it contain?
4. In what color can dyes found in cell sap and plastids stain different parts of plants?
Tasks
Prepare cell preparations of fruits of tomatoes, mountain ash, rose hips. To do this, transfer a particle of pulp to a drop of water on a glass slide with a needle. Divide the pulp into cells with the tip of a needle and cover with a coverslip. Compare the cells of the pulp of fruits with the cells of the skin of onion scales. Note the coloration of the plastids.
Draw what you see. What are the similarities and differences between onion skin cells and fruits?
Do you know that…
The existence of cells was discovered by the Englishman Robert Hooke in 1665. Looking at a thin section of cork (cork oak bark) through a microscope he designed, he counted up to 125 million pores, or cells, in one square inch (2.5 cm) (Fig. 23). In the core of the elder, the stems of various plants, R. Hooke found the same cells. He called them cells. Thus began the study of the cellular structure of plants, but it did not go easily. The cell nucleus was discovered only in 1831, and the cytoplasm in 1846.
Rice. 23. R. Hooke's microscope and the cut of cork oak bark obtained with it
Quests for the curious
You can make your own "historical" preparation. To do this, put a thin section of a light cork in alcohol. After a few minutes, start adding water drop by drop to remove air from the cells - “cells”, darkening the preparation. Then examine the section under a microscope. You will see the same thing as R. Hooke in the 17th century.
§ 8. Chemical composition of the cell
1. What is a chemical element?
2. What organic substances do you know?
3. Which substances are called simple, and which are complex?
All cells of living organisms consist of the same chemical elements that are included in the composition of objects of inanimate nature. But the distribution of these elements in cells is extremely uneven. So, about 98% of the mass of any cell falls on four elements: carbon, hydrogen, oxygen and nitrogen. The relative content of these chemical elements in living matter is much higher than, for example, in the earth's crust.
About 2% of the mass of the cell is accounted for by the following eight elements: potassium, sodium, calcium, chlorine, magnesium, iron, phosphorus and sulfur. Other chemical elements (for example, zinc, iodine) are contained in very small quantities.
Chemical elements combine to form inorganic and organic substances (see table).
Inorganic substances of the cell- it water and mineral salts. Most of all, the cell contains water (from 40 to 95% of its total mass). Water gives the cell elasticity, determines its shape, and participates in metabolism.
The higher the metabolic rate in a particular cell, the more water it contains.
Chemical composition of the cell, %
Approximately 1–1.5% of the total cell mass is made up of mineral salts, in particular salts of calcium, potassium, phosphorus, etc. Compounds of nitrogen, phosphorus, calcium and other inorganic substances are used to synthesize organic molecules (proteins, nucleic acids, etc.). With a lack of minerals, the most important processes of cell vital activity are disrupted.
organic matter are part of all living organisms. They include carbohydrates, proteins, fats, nucleic acids and other substances.
Carbohydrates are an important group of organic substances, as a result of the breakdown of which cells receive the energy necessary for their vital activity. Carbohydrates are part of the cell membranes, giving them strength. Storage substances in cells - starch and sugars also belong to carbohydrates.
Proteins play an essential role in the life of cells. They are part of a variety of cellular structures, regulate life processes and can also be stored in cells.
Fats are stored in cells. When fats are broken down, the energy necessary for living organisms is also released.
Nucleic acids play a leading role in the preservation of hereditary information and its transmission to descendants.
The cell is a "miniature natural laboratory" in which various chemical compounds are synthesized and undergo changes.
INORGANIC SUBSTANCES. ORGANIC SUBSTANCES: CARBOHYDRATES, PROTEINS, FATS, NUCLEIC ACIDS
Questions
1. What are the most abundant chemical elements in a cell?
2. What role does water play in a cell?
3. What substances are classified as organic?
4. What is the importance of organic matter in a cell?
Think
Why is the cell compared to a "miniature natural laboratory"?
§ 9. Vital activity of the cell, its division and growth
1. What are chloroplasts?
2. In what part of the cell are they located?
Life processes in the cell. In Elodea leaf cells, under a microscope, one can see that green plastids (chloroplasts) smoothly move along with the cytoplasm in one direction along the cell membrane. By their movement, one can judge the movement of the cytoplasm. This movement is constant but sometimes difficult to detect.
Observation of the movement of the cytoplasm
You can observe the movement of the cytoplasm by preparing micropreparations of the leaves of elodea, vallisneria, root hairs of water color, hairs of stamen filaments of Tradescantia virginiana.
1. Using the knowledge and skills gained in previous lessons, prepare micropreparations.
2. Examine them under a microscope, note the movement of the cytoplasm.
3. Sketch the cells, arrows indicate the direction of cytoplasmic movement.
The movement of the cytoplasm contributes to the movement of nutrients and air in the cells. The more active the vital activity of the cell, the greater the speed of movement of the cytoplasm.
The cytoplasm of one living cell is usually not isolated from the cytoplasm of other living cells nearby. The threads of the cytoplasm connect neighboring cells, passing through the pores in the cell membranes (Fig. 24).
Between the shells of neighboring cells is a special intercellular substance. If the intercellular substance is destroyed, the cells separate. This is what happens when potatoes are boiled. In ripe fruits of watermelons and tomatoes, crumbly apples, the cells are also easily separated.
Often living growing cells of all plant organs change shape. Their shells are rounded and sometimes move away from each other. In these areas, the intercellular substance is destroyed. Arise intercellular spaces filled with air.
Rice. 24. Interaction of neighboring cells
Living cells breathe, feed, grow and multiply. Substances necessary for the life of cells enter them through the cell membrane in the form of solutions from other cells and their intercellular spaces. The plant receives these substances from the air and soil.
How does a cell divide? The cells of some parts of plants are capable of dividing, due to which their number increases. As a result of cell division and growth, plants grow.
Cell division is preceded by the division of its nucleus (Fig. 25). Before cell division, the nucleus increases, and bodies, usually cylindrical in shape, become clearly visible in it - chromosomes(from the Greek words "chrome" - color and "soma" - body). They transmit hereditary traits from cell to cell.
As a result of a complex process, each chromosome, as it were, copies itself. Two identical parts are formed. During division, parts of the chromosome diverge to different poles of the cell. In the nuclei of each of the two new cells, there are as many of them as there were in the mother cell. All content is also evenly distributed between the two new cells.
Rice. 25. Cell division
Rice. 26. Cell Growth
The nucleus of a young cell is located in the center. In an old cell, there is usually one large vacuole, so the cytoplasm, in which the nucleus is located, is adjacent to the cell membrane, and young cells contain many small vacuoles (Fig. 26). Young cells, unlike old ones, are able to divide.
INTERCELLULAR. INTERCELLULAR SUBSTANCE. CYTOPLASMA MOVEMENT. CHROMOSOMES
Questions
1. How can you observe the movement of the cytoplasm?
2. What is the importance of the movement of cytoplasm in cells for a plant?
3. What are all plant organs made of?
4. Why don't the cells that make up the plant separate?
5. How do substances enter a living cell?
6. How does cell division take place?
7. What explains the growth of plant organs?
8. Where are the chromosomes located in the cell?
9. What role do chromosomes play?
10. What is the difference between a young cell and an old one?
Think
Why do cells have a constant number of chromosomes?
Quest for the curious
Study the effect of temperature on the intensity of cytoplasmic movement. As a rule, it is most intense at a temperature of 37 °C, but already at temperatures above 40–42 °C it stops.
Do you know that…
The process of cell division was discovered by the famous German scientist Rudolf Virchow. In 1858, he proved that all cells are formed from other cells by division. At that time, this was an outstanding discovery, since it was previously believed that new cells arise from the intercellular substance.
One leaf of an apple tree consists of about 50 million cells of different types. There are about 80 different cell types in flowering plants.
In all organisms belonging to the same species, the number of chromosomes in the cells is the same: in house flies - 12, in Drosophila - 8, in corn - 20, in garden strawberries - 56, in river cancer - 116, in humans - 46, in chimpanzees , cockroach and pepper - 48. As can be seen, the number of chromosomes does not depend on the level of organization.
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Even if you've never wondered what our daily food looks like at extreme close-ups, these photographs taken through an electron microscope can impress with their beauty and originality.
The fact is that a simple optical microscope is limited in its resolution by the wavelength of light. A light wave will go around a smaller object, so the reflected signal will not be able to return to the sensor of the device and we will not receive any information. Another thing is when a stream of electrons is directed at the object instead of a beam of light - they are reflected, being comparable in size, and return to the depths of the microscope, carrying with them various information about the object.
The only thing we can no longer, having found ourselves so deep in the microcosm, is to see and distinguish colors, because. they are not really there yet. Therefore, all the bright colors presented in the photographs taken through a scanning electron microscope are the fruit of the work of artists.
Broccoli flower, for example, looks like a tulip. So if your girlfriend has a holiday, and you forgot to buy flowers, you can just get Broccoli out of the fridge and bring a microscope :)
This alien planet is actually nothing but blueberries. This is impressive, but will anyone eat blueberries by the berry after that? You give at once the whole Constellation of Yoghurt!
A grain of salt is an example of a typical fractal shape. Both outside and inside the same pattern of the crystal.
Air mint chocolate. As we can see, inside the small pores of the chocolate are even smaller pores of the mint filling.
Strawberries. In the foreground, a crispy, oily seed. The vague stringiness of this berry is now more than palpable.
Chili pepper "Bird's eye". The smallest representative of Chile looks solid and respectable, it can even be confused with a chocolate bar with nuts.
Raw meat . That's fibers! If it were not for the nutritional value of this product, it would truly be a fabric for clothing.
Cooked meat. But after boiling and frying, the fibers crumble and break, which makes it easier for our teeth and our stomach.
White grapes. Who would have thought that this homogeneous jelly inside a grape has such a porous character. Probably, it is microporosity that creates that familiar sensation of tingling of the tongue (as if the bubbles are exploding).
Graceful and spicy, saffron looks like a bark dump from a woodworking factory. A piquant piece of gigantic wood.
Dried anise fruit reveals a resemblance to a cephalopod that has too many legs.
coffee granules. Even knowing what it really is, it's still hard to believe: these gentle lips painted with hieroglyphs are amazing! If granulated coffee companies put such photos on their packaging, they would most likely be able to significantly increase their sales.
Sugar . The fractal brother of salt crystals. Who says that nature does not tolerate right angles?
Sweetener "Aspartame". So think: can an uneven, holey ball replace a polished cube or parallelepiped?
Tomato . Or is it a honeycomb of red Martian bees? Scientists do not yet know the exact answer to this question.
A roasted coffee bean just asks to have a nut placed in its microcells and concreted with cream on the outside.
Romanesco cabbage. Perhaps this is the only product similar to itself in the macrocosm.
Almonds are layers of heat-resistant carbohydrate boards. If they were bigger, it would be possible to build a house.
If almonds are the house, then the powdered sugar on the cupcake is upholstered furniture. Why does all junk food look so cozy?
Onion . As you can see, these are rather rough layers of sandpaper. So say those who do not like onions. Others will note the similarity with velvet carpets.
The radish crumbles from the inside into whole deposits of precious stones and volcanic rocks.
So, we are convinced that our everyday food in a highly exaggerated form evokes persistent associations with rocks, minerals and even space objects. And what if one day - in the bowels of the Universe - we discover entire planets and star systems entirely consisting of organic matter, including food? We just have to be ready for it! The development of food spaces and the colonization of the edible landscape is the main topic of research by the famous American photographer and writer Christopher Boffoli. He called his collection "Inconsistency", by the way, figures of people were attached to the surface with agave nectar.
The repair team inspects a broken egg. Nothing can be done: now this hole will have to be patched up.
Banana roads promise to be the most convenient overpass for cyclists.
Robbery in the fig district. They didn't even lock the doors at night.
Be careful near melon dips.
The candy field scouts move confidently and assess the scale of the development.
Children play in the snow on cupcake hill. Make sure no one falls down or catches a cold.
Task 1. Examining the skin of an onion.
4. Draw a conclusion.
Answer. The skin of an onion is made up of cells that fit snugly together.
Task 2. Examining the cells of a tomato (watermelon, apple).
1. Prepare a micropreparation of fruit pulp. To do this, separate a small piece of pulp from a cut tomato (watermelon, apple) with a dissecting needle and place it in a drop of water on a glass slide. Spread with a dissecting needle in a drop of water and cover with a coverslip.
Why are flowers colored and leaves green?
Thus, all living beings are composed of microscopic units, cells and each cell have the characteristic properties of living things. On the other hand, some microscopic living beings are formed from a single cell. In other words, if we want to observe cells, any specimen of a living being could do the job. The examples below are well suited to the fabrication referred to elsewhere, but it goes without saying that if we have a tool of the trade. The observations described here will only be more convenient.
Answer. What to do. Take the pulp of the fruit. Put it in a drop of water on a glass slide (2).
2. Examine the micropreparation under a microscope. Find individual cells. Examine the cells at low magnification and then at high magnification.
Like the apidologist and his tens of billions of neurons, he is lateral. This certainly applies to the rich social life that leads. Their manipulation basically consisted of observing the social interactions of two workers, recently captured on their flight from the same hive or not, each locked in a petri box that had a hole pierced on the side. Once the two holes hit a match, there is an encounter that is either "friendly" drawing the tongue or "hostile" one making a big back, mandibles and stinger in front.
Note the color of the cell. Explain why a drop of water changed its color and why did this happen?
Answer. The color of the cells of the pulp of watermelon is red, apples are yellow. A drop of water changes its color because it enters the cell sap contained in the vacuoles.
3. Draw a conclusion.
Answer. A living plant organism is made up of cells. The content of the cell is represented by a semi-liquid transparent cytoplasm, in which there is a denser nucleus with a nucleolus. The cell membrane is transparent, dense, elastic, does not allow the cytoplasm to spread, gives it a certain shape. Some parts of the membrane are thinner - these are pores, through which communication between cells occurs.
The bees were prepared: the straight antenna was cut off at the base or on the left side of the antenna. The contact of two workers with a direct antenna is faster and more often friendly than in the case of 2 amputees. Then more often there is a negative reaction, even if they are sisters. The right antenna appears to be specialized in odor, food, and colony recognition, and the aggressiveness shown by individuals with only the left would be due to the inability to olfactorily identify the sister.
Perhaps this asymmetry also plays a role in dance communication: the subject is digging. Source article: "Right Antenna for Social Behavior in Bees". The phenomenon can be fatal in other circumstances: the insect's positive charges attract the web. Among the test objects, insects and cobwebs: the stick attracts the canvas. The rest takes place in his lab with his colleague Robert Dudley. With the same magic wand, they positively load dead insects - bees, green flies, aphids, fruit flies, as well as drops of water and make them fall in front of a diadem-stretched canvas stretched over a frame.
Thus, a cell is a structural unit of a plant.
What are the cells as the main elements - "bricks". Shell, cytoplasm, nucleus, vacuoles. spare substances. Protein grains. Drops of oil. starch grains.
Substances that make up the cell. Water. Pigments. Intercellulars. plant tissues. Cover fabrics. storage fabrics. Mechanical (support) fabrics.
We have previously cut carrots and apples in order to take a closer look at the internal structure of these fruits. The same can be done now with watermelon, before enjoying its taste. Why watermelon? It is best suited to provide visibility on our topic − cellular structure of organs plants.
And if you carefully look at the resulting sections of watermelon, apple, carrot, tomato ..., then even without using a magnifying glass you can see that the pulp of these fruits consists of very small particles. These are the cells - very small particles that make up the fruits in question.
Figuratively speaking, cells are small parts (“bricks”) that are arranged in a certain way and make up the “body” of all plants and flowers as living organisms. The cellular structure of plants was discovered in the 17th century only thanks to the invention of such a wonderful device as a microscope. In this photo you can look at a conventional light microscope:
So. If you look at the contents of the pulp of watermelons (and you can also tomatoes) through the light microscope presented above, magnifying the picture by 50-60 times, you can clearly see and distinguish transparent cells that have rounded shapes. Moreover, these cells are of different colors. In our considered tomatoes or watermelons, these colors are pale pink, while in apples, for example, they are already colorless. All the cells, being in a kind of "slurry", lie loosely. Moreover, they are located in such a way that they are not connected to each other and it is very clearly visible that each cell individually has its own shell (wall).
Angela imported them from South America to Oak Ridge and acclimated them. In any case, she said that she was very pleased, and her commitment to biological control was in the role of honor. Zooscopy: the wind billows, the whips of ravens, the waste of crayfish, the jumping of carps, the frog stands at the top of his ladder. It's depression, no need for a barometer. These last three cases owe nothing to popular wisdom.
The movements and radiation of premodulating pheromones are attenuated so that there is no copulation. Modified Sexual behavior in response to changes in atmospheric pressure. What is new is that this instrument is powered by the contraction of an insect muscle irrigated with a nutrient fluid. It is difficult to prevent the latter from evaporating, but it was possible to apply a paraffin film to seal the device. In full autonomy, this biodrive works for 5 hours. And even in harsh conditions. And better and safer than mechanical clamps of the same size.
The structure of a plant cell.
Armed again with the same microscope, one can see and examine the internal, so-called "living contents" of plant cells. As we noted earlier, the shell surrounds the "body" of the cell. A colorless cytoplasm is enclosed in the space under the membrane. The cytoplasm also has its inclusions. It is clearly possible to observe a denser lump in it - this is the core. There are also transparent vesicles - these are vacuoles that are filled with cell sap. Why is watermelon pink or even red? Yes, because the cell juice in the watermelon cells has just such colors.
Works by Keisuke Morishima and colleagues at Osaka University. It also removes pores and makes them less visible. By mixing cork juice into a regular cream or lotion, you get a cream that helps get rid of fine lines and moisturizes well. The silicates and sulfur in the stones promote healthy hair growth.
Natural ascorbic acid and caffeic acid inhibit water retention in the skin, reducing or eliminating swelling. Cucumbers also help fight cellulite. The best combination is the consumption of cucumbers, cocoa juices and bars on cellulite sites. Cucumber from these places releases excess fluid and collagen, which makes the skin look better and refreshed.
But with tomatoes, everything is different. In them, the cell sap in the cells is colorless. But in the cytoplasm, very small and reddish-colored "bodies" are visible. These bodies are called plastids. Plastids can also have different colors. In tomatoes, plastids are colored, while in other representatives of the flora they are also colorless.
Let's take chloroplasts in Elodea leaf cells as an example. See photo:
Famous Greek delicacy Tzatziki. The most famous cucumber preparation is chopped lettuce. Each country has different rules for its preparation. In India, cucumber is paired with refreshing yogurt and served with spicy curries and turmeric to soften the taste. In Scandinavia, as well as in the Caucasus, dense sour cream is added to the salad, and in France - salty whipped cream. Some families in Bulgaria will kiss her with baked curd mixed with olive oil. Delicious mixture of cucumber with yogurt and tanned garlic - traditional Greek tsaziks.
If you look at an elodea leaf under a microscope, you can see the following picture. The leaf consists of only two layers of cells. These cells are more reminiscent of rectangles that are elongated and fit rather tightly to each other. The cytoplasm is transparent and green plastids are visible in it - these are the so-called chloroplasts. They look great in this photo.
Cucumber is also good for making appetizers, cold soups or sauces. The drug is the same as in the case of pumpkins. If cucumbers crumble in some dishes, prepare them before the start. If they are not consumed, they should be immediately refrigerated. If you need to remove the juice, such as when preparing a try, never reel it in.
You can make a cucumber preparation according to your personality type. For the fire and wind of nature is good, but add to the cold cucumber yogurt, cottage cheese and cream and tartar sauce and dill, green onions, onions and various herbs. For calmer earth and water people, you can add garlic, hot peppers, and various hot spices. Of course, it depends on the season and the current state of the person.
In general, the word "chloroplast" comes from a combination of two Greek words. "chloros" - green and "plastos" - decorated. There are a lot of chloroplasts and it is even difficult to see the nucleus in the cell. It should be noted that in each living cell of plants there is only one, any type of plastid. These plastids are either colorless or colored. Their color can be yellow, and red, and orange, and green. It is precisely thanks to these plastids that all plant organs have one color or another.
A great and refreshing salad without yogurt, cream or cottage cheese. Just water, apple cider vinegar or lemon juice, salt, some honey and favorite herbs like thyme, mint, lemon balm, a few dandelion leaves. As a bowl in summer, cucumber and carrot rectangles soaked in various dressings and dips.
Unusually, but tasty, chocolate sticks are filled with caramel and sprinkled with roasted almonds. Heat up some cucumbers, salt, add a pinch of cayenne spice and a few ice cubes. Mix cucumber with mint and add soda. Garnish with lime and brown sugar.
Spare substances located in the cell.
In cells, certain substances are deposited in large quantities, which are not used immediately. It is these substances that are called reserve substances.
Most often found as a storage substance in the cell starch .
For clarity, let's do the same experiment with cutting potatoes. On a cut of a potato tuber, such a picture is very clearly observed. In the thin-walled cells of the pulp, there are quite a lot of colorless, but large oval-shaped grains. These are starch grains that have a layered structure. See photo:
Juice juice dipped in the taste of pineapple juice is also excellent, it can also be made from compote. Of course, the correct one is healthier. Supports weight loss well. Cucumber milk is also great for marjoram. Broken yogurt with shellfish, salt and bark supplemented with a mineral aids digestion.
Beware, for some gallbladders, daily consumption of cucumber is inappropriate. Cucumbers are hard to digest for them and can overcome them. Beware - when buying a cucumber, first find out where it comes from. The best from Slovakia or the Czech Republic and from the nearest place of residence. Then you need to know if it is organic quality - that means it is not sprayed with pesticides by many, because it is best treated with cucumbers and zest. It contains most of the silicon and potassium. If the cucumber is of "unknown" origin, it's best to remove it from the skin because you won't be getting rid of pesticides.
All starch accumulates in colorless plastids. Moreover, the very shapes and sizes of starch grains located in the cells of various plants are not the same.
Good taste and a lot of imagination in preparation. After leaving school, he entered as a regular postgraduate researcher at the Center for Hygiene and Occupational Diseases of the Institute of Hygiene and Epidemiology. In the same year, he testified about hygiene and epidemiology - the first degree of attestation. During this period, he developed instruments for exposing the magnetic field for the experimental part of his work.
He worked as a secondary doctor and developed apparatus and methods for applying pulsed magnetic fields. This activity also led to patents for magnetotherapy devices. Institute of Hygiene and Epidemiology in Prague 10. As a scientist, laboratory of ecotoxicology with the task of studying the biological activity of reactive oxygen species. He developed a new enzymatic method for the determination of catalase in biological samples. He developed and patented an analytical luminometer which was made in a small series for the above purposes.
In the cells of the seeds of oil plants (flax, sunflower) there are droplets spare oil, which are concentrated in cytoplasm .
In the so-called "cell juice" are able to accumulate spare proteins. At the time when the seeds ripen and the vacuoles dry up, they turn into hard protein grains. Starch grains and protein grains are different from each other. If we conduct an iodine test, we will see that the starch grains turn blue. And protein grains turn yellow.
As part of the supporting program, the laboratory, together with the development program, to predict the spread of toxic clouds in the framework of possible accidents in the chemical industry. Boyar adviser of the department of magnetotherapy. He designed and assembled a portable magnetometer for hygienic maintenance. These reports served as the basis for approval by the Chief Hygienist of the Czech Republic.
During this period, he completed courses in medical statistics and epidemiological methods for noncommunicable diseases. He has done research on the possibilities of physiotherapy for fibromyalgia. He worked on a project to assess the psychophysical load in the subway. The Ministry of Health obtained specialist qualifications to perform the medical profession in the field of hygiene and epidemiology, and also granted the request for inclusion in special education in the field of rehabilitation and physical medicine.
We get the same picture if we treat a cut of pea seeds with an iodine solution. The storage protein can also be deposited in colorless plastids.
So, let's sum up. In the various examples considered, it can be seen that a cell (as a living organism) consists of several components:
- The internal contents of the cell (also called "living contents") is almost liquid and at the same time transparent in appearance. cytoplasm. In the cytoplasm, the nucleus is already quite dense in composition. There are also numerous vacuoles and plastids. By the way, the word "vacuoles" comes from the Latin "vacuus" - empty.
- All cells have various inclusions in their "living contents". These inclusions are most often deposits of reserve substances for "nutrition" - protein grains, drops of oil and starchy grains.
- The wall of the cells (or their shell), as a rule, is transparent in appearance, very elastic and dense. Therefore, the wall keeps the cytoplasm from spreading. Thanks to shell cell and has one form or another.
To give a short description cage, then we can say that:
The cell is the main element - the "brick" of the structure of any plant.
The cell consists of the nucleus, cytoplasm, plastids, various inclusions. And all this “community” is enclosed in a shell.
composition of plant cells. Basic tissues of a plant cell.
Substances that make up the plant cell.
All living plant cells contain a sufficient amount of water (H2O). The volume of water in the cells as a percentage can reach 70% - 90% of the dry weight of the plant. Moreover, the shell is largely inferior to vacuoles in terms of water content.
In the so-called live content » cells are predominant squirrels , and there are also fatty substances .
Cells also contain their own “colors”, i.e. dyes called pigments . One part of the pigments is found in colored plastids, and the other part of these pigments is in a dissolved state in the cell sap of vacuoles. Here is one specific example. Chloroplasts (green plastids) contain the pigment chlorophyll. It got its name from a combination of two Greek words. First word " chloros"- translates as green. The second word phyllon". Can be translated as a sheet.
In the cell sap of vacuoles are dissolved in large quantities and organic matter , and minerals .
The composition of the plant cell membrane is mainly determined by the presence of fiber, which is also called cellulose.
Intercellulars.
All the cells that make up a plant are interconnected. But the substance that carries out this intercellular communication is called intercellular. In some cases (elodea leaves), this connection turns out to be quite strong, while in others (for example, tomatoes, watermelons), the connection is no longer so strong.
In those plants where such not very strong (loose) connections are present, empty spaces are formed between the cells, which can be of different sizes. These spaces between plant cells are called intercellular . Basically, the intercellular spaces are filled with air. Much less water.
plant tissues.
In general, a tissue is a group of cells that are interconnected in a certain way. These cells are designed to perform very specific functions in the plant body.
Let's take for example a very well-known bow. So. The peel of the scales at the bulb is a visual representation of the tissue. If we examine the skin under a microscope, it turns out that it consists of a single layer of cells, oblong in appearance. But these cells are very close to each other, as if forming a protective barrier. From this we can conclude that the skin of the bulb performs protective functions.
These are the skins that are on the surface of flowers and plants and perform the function of protection, called integumentary tissues. It is not difficult to draw such a conclusion - integumentary tissue is present in all plants and flowers.
Here's another example of cover fabric. The photo shows the skin of a leaf no less familiar to all Tradescantia. The integumentary tissue of the tradescantia leaf protects it from aggressive environmental influences (mechanical damage, drying, penetration of harmful microorganisms into tissues).
Let us also take the well-known fruits of plants. Why are some of them very juicy? And this happens because reserve substances accumulate in the pulp cells of such fruits. This process takes place in the tissues of the body. Plant tissues, in the cells of which reserve substances are formed, are called - storage tissues.
But not all fruits are so juicy. Imagine, for example, nuts, acorns, apricot pits, and plums. All of them have shells. And the shell, in turn, is formed due to cells that have very thick walls and at the same time form a continuous hard tissue. These fabrics are called supporting or mechanical. In this photo you can observe the cells of the mechanical tissue.
Now you have an idea about the three main types of plant tissues.
lesson type - combined
Methods: partially exploratory, problem presentation, reproductive, explanatory-illustrative.
Target:
Students' awareness of the importance of all the issues discussed, the ability to build their relationship with nature and society based on respect for life, for all living things as a unique and priceless part of the biosphere;
Tasks:
Educational: to show the multiplicity of factors acting on organisms in nature, the relativity of the concept of "harmful and beneficial factors", the diversity of life on planet Earth and the options for adapting living beings to the whole range of environmental conditions.
Developing: develop communication skills, the ability to independently acquire knowledge and stimulate their cognitive activity; the ability to analyze information, highlight the main thing in the studied material.
Educational:
Formation of an ecological culture based on the recognition of the value of life in all its manifestations and the need for a responsible, careful attitude to the environment.
Formation of understanding of the value of a healthy and safe lifestyle
Personal:
education of Russian civil identity: patriotism, love and respect for the Fatherland, a sense of pride in their homeland;
Formation of a responsible attitude to learning;
3) Formation of a holistic worldview, corresponding to the current level of development of science and social practice.
cognitive: the ability to work with various sources of information, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.
Regulatory: the ability to organize independently the execution of tasks, evaluate the correctness of the work, reflection of their activities.
Communicative: Formation of communicative competence in communication and cooperation with peers, older and younger in the process of educational, socially useful, teaching and research, creative and other activities.
Planned results
Subject: know - the concepts of "habitat", "ecology", "environmental factors" their influence on living organisms, "connections of living and non-living";. Be able to - define the concept of "biotic factors"; characterize biotic factors, give examples.
Personal: make judgments, search and select information; analyze connections, compare, find an answer to a problematic question
Metasubject:.
The ability to independently plan ways to achieve goals, including alternative ones, to consciously choose the most effective ways to solve educational and cognitive problems.
Formation of the skill of semantic reading.
Form of organization of educational activities - individual, group
Teaching methods: visual and illustrative, explanatory and illustrative, partially exploratory, independent work with additional literature and textbook, with DER.
Receptions: analysis, synthesis, conclusion, transfer of information from one type to another, generalization.
Practical work 4.
MANUFACTURE OF A MICROPREPTION OF THE FRUIT OF THE FRUIT OF TOMATO (WATERMELON), STUDYING IT WITH THE HELP OF A LOUP
Objectives: to consider the general view of a plant cell; to learn to depict the considered micropreparation, to continue the formation of the skill of independent production of micropreparations.
Equipment: magnifying glass, soft cloth, glass slide, coverslip, glass of water, pipette, filter paper, pre-steaming needle, piece of watermelon or tomato fruit.
Progress
cut the tomato(or watermelon), using a dissecting needle, take a piece of pulp and put it on a glass slide, drop a drop of water with a pipette. Mash the pulp until a homogeneous gruel is obtained. Cover the slide with a cover slip. Remove excess water with filter paper
What do we do. Let's make a temporary micropreparation of a tomato fruit.
Wipe the glass slide and coverslip with a paper towel. Pipette a drop of water onto a glass slide (1).
What to do. With a dissecting needle, take a small piece of fruit pulp and place it in a drop of water on a glass slide. Mash the pulp with a dissecting needle until a slurry is obtained (2).
Cover with a cover slip, remove excess water with filter paper (3).
What to do. Examine the temporary micropreparation with a magnifying glass.
What we observe. It is clearly seen that the pulp of the tomato fruit has a granular structure.
(4).
These are the cells of the pulp of the tomato fruit.
What we do: Examine the micropreparation under a microscope. Find individual cells and examine at low magnification (10x6), and then (5) at high magnification (10x30).
What we observe. The color of the tomato fruit cell has changed.
Changed its color and a drop of water.
Conclusion: The main parts of a plant cell are the cell membrane, the cytoplasm with plastids, the nucleus, and the vacuoles. The presence of plastids in the cell is a characteristic feature of all representatives of the plant kingdom.
Living cell of watermelon pulp under the microscope
Watermelon under the microscope: macro photography (10x magnification video)
Appleundermicroscope
Manufacturingmicropreparation
Resources:
I.N. Ponomareva, O.A. Kornilov, V.S. Kuchmenko Biology: Grade 6: a textbook for students of educational institutions
Serebryakova T.I., Elenevsky A. G., Gulenkova M. A. et al. Biology. Plants, Bacteria, Fungi, Lichens. Trial textbook for grades 6-7 of high school
N.V. Preobrazhenskaya Biology workbook for the textbook by V. V. Pasechnik “Biology Grade 6. Bacteria, fungi, plants
V.V. Pasechnik. Manual for teachers of educational institutions Biology lessons. 5th-6th grades
Kalinina A.A. Lesson developments in biology Grade 6
Vakhrushev A.A., Rodygina O.A., Lovyagin S.N. Verification and control work to
textbook "Biology", 6th grade
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