Drawing of the flesh of a watermelon with the naked eye. Apple under a microscope

Prepare a temporary preparation of tomato pulp. To do this, remove the skin from the surface of a ripe tomato with tweezers, take a little pulp with the end of a scalpel, transfer it to a drop of water on a glass slide, distribute it evenly with a dissecting needle, cover with a cover glass and examine it under a microscope at low and high magnification. You will see that the cells are mostly round in shape and have a thin membrane.

Consider the nucleus and nucleolus, immersed in granular cytoplasm located along the cell walls, as well as in the form of strands crossing the cell. Between the strands of cytoplasm there are vacuoles with colorless cell sap. Organelles are visible in the cytoplasm – chromoplasts of various shapes, orange or reddish in color, which take part in the metabolic process. Their color depends on the pigments - carotene ( orange-red) and xanthophyll (yellow). Chromoplasts of tomato and rose hips contain the carotene isomer lycopene. In unripe fruits, chromoplasts have a round shape. As the pigment matures, it crystallizes, lags behind the wall and turns into needle-like formations.

EXERCISE. Draw several tomato cells with chromoplasts.

Inscription above the picture: Cells from tomato pulp (Lycopersicum esculentum Mill). Temporary microslide. X100 and x400.

The figure should indicate the shell, nucleus, cytoplasm, and chromoplasts.

Work 2.3. Microscopy of human blood cells

Examine the finished Romanovsky-Giemsa-stained human blood preparations under a microscope with x10, x40, x100 lenses. The bulk of cells in the field of view are red blood cells – red blood cells . In this preparation, the cytoplasm of erythrocytes is colored dark blue. There are no nuclei (the precursors of erythrocytes have them, but they lose them during maturation). Central part erythrocytes have a zone of clearing, which indicates the biconcave structure of these cells.

Among red blood cells, larger white ones are occasionally found blood cells - leukocytes , the shape of which varies from round to amoeboid. Their main function is phagocytosis . The cytoplasm of leukocytes is colored pinkish. They contain a dark red core. In some leukocytes, the nuclei resemble rods, in others they are divided into segments. There are also lymphocytes – immunological memory cells. They have a very large round shape, dark red nucleus, cytoplasm looks like a thin ring-shaped or crescent-shaped rim.

EXERCISE. Draw several red blood cells, white blood cells with nuclei of different shapes and lymphocytes.

Inscription above the picture: Human blood cells (Homo sapiens). Permanent microslide. Fixation with ethanol. Romanovsky-Giemsa staining. X1000.

Materials presented in the laboratory report

1. Completed table “Main organelles and structural components cells." When filling out the table, note the differences in the occurrence of some organelles in higher and higher lower plants(for example: for the higher ones - “-”, for the lower ones - “+”).

2. Sketch of a microslide of Vallisneria (Elodea) cells.

3. Sketch of a microscopic specimen of tomato pulp cells.

4. Sketch of a microscopic specimen of human blood cells.

Table 1

Major organelles and structural components of the cell

Organelles and structural components		Presence in cells...
		prokaryote	eukaryotes
		prokaryote	vegetable	animals
1. Cell wall	1. Frame (gives shape to the cell). 2. Protection from mechanical damage.
2. Cytoplasmic membrane
3. Glycocalyx

5. Nucleolus
6. Cytosol
7. Cytoskeleton: microtubules, microfilaments
8. Mitochondria
9. EPS granular
10. EPS smooth
11. Golgi apparatus
12. Ribosomes
13. Centrioles
14. Flagella
15. Eyelashes
16. Inclusions
17. Vacuoles
18. Leukoplasts
19. Chromoplasts
20. Chloroplasts

TOPIC 3

REPRODUCTION OF ORGANISMS. CELL DIVISION.

MITOSIS. MEIOSIS

Lesson objectives:

1. Study the main forms of asexual and sexual reproduction.

2. Study the mitotic cycle of a cell, learn to distinguish the phases of mitosis on temporary preparations of plant root cells.

3. Study the structural features of metaphase chromosomes.

4. Study the main stages of meiosis.

Questions and tasks for self-study

1. Compare asexual and sexual reproduction.

2. Forms asexual reproduction, their features and significance.

3. Forms of sexual reproduction, their characteristics and significance.

4. Types of tissues according to mitotic activity. Reserve pool of cells.

5. Cellular and mitotic cycle, its phases and periods.

6. Causes of mitosis. Phases of mitosis.

7. Biological significance of mitosis. Amitosis, endomitosis, polyteny.

8. The structure of metaphase chromosomes, their classification.

9. Meiosis, main phases and stages of division I.

10. Meiosis, main phases of division II.

11. Differences between mitosis and meiosis.

12. Biological significance of meiosis.

13. Formation of male and female germ cells, characteristics of the main stages, similarities and differences.

14. Place of meiosis in life cycle organisms.

Please write a conclusion about a piece of fruit pulp under a magnifying glass

Even with the naked eye, or even better under a magnifying glass, you can see that the flesh of a ripe watermelon consists of very small grains, or grains. These are cells - the smallest “building blocks” that make up the bodies of all living organisms.
If you examine the pulp of a tomato or watermelon with a microscope magnifying approximately 56 times, round transparent cells are visible. In apples they are colorless, in watermelons and tomatoes they are pale pink. The cells in the “mush” lie loosely, separated from each other, and therefore it is clearly visible that each cell has its own membrane, or wall.
Conclusion: Living cell plants has:
1. Living contents of the cell. (cytoplasm, vacuoles, nucleus)
2. Various inclusions in the living contents of the cell. (deposits of spare nutrients: protein grains, oil drops, starch grains.)
3. Cell membrane, or wall. (It is transparent, dense, elastic, does not allow the cytoplasm to spread, and gives the cell a certain shape.)
Even with the naked eye, or even better under a magnifying glass, you can see that the flesh of a ripe watermelon consists of very small grains, or grains. These are cells - the smallest “building blocks” that make up the bodies of all living organisms.
If you examine the pulp of a tomato or watermelon with a microscope magnifying approximately 56 times, round transparent cells are visible. In apples they are colorless, in watermelons and tomatoes they are pale pink. The cells in the “mush” lie loosely, separated from each other, and therefore it is clearly visible that each cell has its own membrane, or wall.
Conclusion: A living plant cell has:
1. Living contents of the cell. (cytoplasm, vacuoles, nucleus)
2. Various inclusions in the living contents of the cell. (deposits of reserve nutrients: protein grains, drops of oil, starch grains.)
3. Cell membrane, or wall. (It is transparent, dense, elastic, does not allow the cytoplasm to spread, and gives the cell a certain shape.)
the cells are very large
Cells are seen better when viewed under a magnifying instrument.

While studying plant science, botany and carpology in practice, it is interesting to touch upon the topic of the apple tree and its multi-seeded, indehiscent fruits, which humans have eaten since ancient times. There are many varieties, the most common type is “domestic”. It is from it that manufacturers all over the world make canned food and drinks. Looking at the apple under 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 of flower development on the apple tree, occurring after double fertilization. Formed from the ovary of the pistil. From it the pericarp (or pericarp) is formed, which performs 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 is a semi-liquid medium of organic and inorganic substances. For example, salts, monosaccharides, carboxylic acids. It combines all components into one biological mechanism, providing endoplasmic cyclosis.
A vacuole is an empty space filled with cell sap. She organizes salt metabolism and serves to remove metabolic products.
The nucleus is the carrier of genetic material. It is surrounded by a membrane.

Methods of observation apple under a microscope:

Transmitted lighting. The light source is located under the test drug. The microsample itself must be very thin, almost transparent. For these purposes, a slice is prepared using the technology described below.

Preparation of a microslide of apple pulp:

Use a scalpel to make a rectangular incision and carefully remove the skin with tweezers;
Using a medical dissecting needle with a straight tip, transfer a piece of flesh to the center of the slide;
Using a pipette, add one drop of water and a dye, for example, brilliant green solution;
Cover with a coverslip;

Microscoping is best started with low magnification 40x, gradually increasing the magnification up to 400x (maximum 640x). The results can be recorded digitally by displaying the image on a computer screen using an eyepiece camera. It is usually purchased as an additional accessory and is characterized by the number of megapixels. It was used to take the photos presented in this article. 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.

If you examine the pulp of a tomato or watermelon with a microscope magnifying approximately 56 times, round transparent cells are visible. In apples they are colorless, in watermelons and tomatoes they are pale pink. The cells in the “mush” lie loosely, separated from each other, and therefore it is clearly visible that each cell has its own membrane, or wall.
Conclusion: A living plant cell has:
1. Living contents of the cell. (cytoplasm, vacuoles, nucleus)
2. Various inclusions in the living contents of the cell. (deposits of reserve nutrients: protein grains, drops of oil, starch grains.)
3. Cell membrane, or wall. (It is transparent, dense, elastic, does not allow the cytoplasm to spread, and 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 viewing with it cellular structure plants.

1. Examine a hand-held magnifying glass. What parts does it have? What is their purpose?

A hand magnifying glass 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 a distance at which the image of the object through the magnifying glass is most clear.

2. Examine with the naked eye the pulp of a semi-ripe tomato, watermelon, or apple. What is characteristic of their structure?

The pulp of the fruit is loose and consists of tiny grains. These are cells.

It is clearly visible that the pulp of the tomato fruit has a granular structure. The apple's pulp is slightly juicy, and the cells are small and tightly packed together. The pulp of a watermelon consists of many cells filled with juice, which are located either closer or further away.

3. Examine pieces of fruit pulp under a magnifying glass. Draw what you see in your notebook and sign the drawings. What shape do the fruit pulp cells have?

Even with the naked eye, or even better under a magnifying glass, you can see that the flesh of a ripe watermelon consists of very small grains, or grains. These are cells - the smallest “building blocks” that make up the bodies of all living organisms. Also, the pulp of a tomato fruit under a magnifying glass consists of cells similar to rounded grains.

Laboratory work No. 2. The structure of a microscope and methods of working with it.

1. Examine the microscope. Find the tube, eyepiece, lens, tripod with stage, mirror, screws. Find out what each part means. Determine how many times the microscope magnifies the image of the object.

Tube is a tube that contains the eyepieces of a microscope. Eyepiece - element optical system, facing the observer's eye, the part of the microscope designed to view the image formed by the mirror. The lens is designed to construct an enlarged image with accurate reproduction of the shape and color of the object of study. A tripod holds the tube with an eyepiece and objective at a certain distance from the stage on which the material being examined is placed. The mirror, which is located under the object stage, serves to supply a beam of light under the object in question, i.e., it improves the illumination of the object. Microscope screws are mechanisms for adjusting the most effective 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. You should work with a microscope while sitting;

2. Inspect the microscope, wipe the lenses, eyepiece, mirror from dust with a soft cloth;

3. Place the microscope in front of you, slightly to the left, 2-3 cm from the edge of the table. Do not move it during operation;

4. Open the aperture completely;

5. Always start working with a microscope at low magnification;

6. Lower the lens to the working position, i.e. at a distance of 1 cm from the 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 illuminate the field of view as much as possible and evenly;

8. Place the microspecimen on the stage so that the object being studied is under the lens. Looking from the side, lower the lens using the macroscrew until the distance between the lower lens of the lens and the microspecimen becomes 4-5 mm;

9. Look into the eyepiece with one eye and rotate the coarse aiming screw towards yourself, smoothly raising the lens to a position at which the image of the object can be clearly seen. You cannot look into the eyepiece and lower the lens. The front lens may crush the cover glass and cause scratches;

10. Moving the preparation with your hand, find right place, place it in the center of the microscope field of view;

11. After finishing work with high magnification, set the magnification to low, raise the lens, remove the specimen from the work table, wipe all parts of the microscope with a clean napkin, and cover it plastic bag and put it in the closet.

3. Practice the sequence of actions when working 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. Use a mirror to shine light into the opening of the stage.

2. Place the prepared preparation on the stage and secure the slide with clamps.

3. Using the screw, smoothly lower the tube so that the lower edge of the lens is at a distance of 1-2 mm from the specimen.

4. Look into the eyepiece with one eye without closing or squinting the other. While looking through the eyepiece, use the screws to slowly lift the tube until a clear image of the object appears.

5. After use, put the microscope in its case.

Question 1. What magnifying devices do you know?

Hand magnifier and tripod magnifier, microscope.

Question 2. What is a magnifying glass and what magnification does it provide?

A magnifying glass is the simplest magnifying device. A hand magnifying glass consists of a handle and a magnifying glass, convex on both sides and inserted into a frame. It magnifies objects 2-20 times.

A tripod magnifying glass magnifies objects 10-25 times. Two magnifying glasses are inserted into its frame, mounted on a stand - a tripod. A stage with a hole and a mirror is attached to the tripod.

Question 3. How does a microscope work?

Into the telescope, or tube, of this light microscope magnifying glasses (lenses) are inserted. At the upper end of the tube there 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, you can see an image of an object illuminated by this mirror.

Question 4. How to find out what magnification a microscope gives?

To find out how much the image is magnified when using a microscope, you need to multiply the number indicated on the eyepiece by the number indicated on the objective lens you are using. For example, if the eyepiece gives 10x magnification and the objective gives 20x magnification, then overall increase 10 x 20 = 200 times.

Think

Why can't we study opaque objects using 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 stage and hit the lens system of the objective and eyepiece. And light does not pass through opaque objects, and therefore we will not see an image.

Quests

Learn the rules of working with a microscope (see above).

Using additional sources of information, find out what details of the structure of living organisms can be seen with the most modern microscopes.

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, allowing you to view molecules and electrons. And an electron scanning 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 surface layer of the surface under study.