The role of microorganisms in practical human activities presentation. The role of bacteria in nature and human life Introducing different groups of bacteria and their role. Prevention of infectious diseases

Is it possible to exist
modern biosphere and
human in it without bacteria?

Task 2. Write the name of the forms of bacterial cells.

Bacteria of decay and decomposition

Soil bacteria

Nitrogen-fixing bacteria

Lactic acid bacteria

Lactic acid bacteria

Various types of bacteria cause food spoilage. Botulism is a disease caused by products contaminated with botulism bacilli.

Bacteria spoil the hay in the stacks. Books in book depositories suffer from them.

Pathogenic bacteria

Bacterial plant diseases

Bacterial diseases of animals and humans

Plague

Sources of infection

Cholera

Sources of infection

anthrax

Sources of infection

Tuberculosis is one of the oldest infectious diseases

Factors contributing to tuberculosis disease

Routes of infection

Prevention of infectious diseases

Answer: Life without bacteria on Earth is impossible. a) Bacteria played a key role in the creation of soil. b) bacteria decompose organic matter

Learning new material

1. Communicating the topic and setting lesson objectives together with students (2 minutes)

To find out the topic of the lesson you need to guess the riddle: the stable is full of white sheep (teeth)…

What associations do you have in connection with the word teeth? (the teacher writes down all the words proposed by the students on the board)

What can we talk about in class? (formulation of lesson objectives together with children)

2. Updating knowledge (3 minutes)

Since the topic of our lesson is “Structure, functions and hygiene of teeth,” let's remember what we learned on this issue from past courses. You studied organ systems in 7th grade, got acquainted with the organ systems of animals, so let's remember the types of teeth in mammals.

We see that teeth are differentiated only in mammals. And their shape depends on the animal’s feeding methods. The function of mammalian teeth affected the nature of their attachment to the jaws and the characteristics of tooth replacement. Typically, mammalian teeth sit in the alveoli of the jaws and are strengthened by the connective tissue surrounding the teeth.

Note to teacher:

(the teacher uses additional material about animal teeth presented in the lesson notes in full, if the level of development of the class’s knowledge of knowledge of the class allows)

In representatives of different orders of mammals, the number of teeth varies greatly: a decrease or increase in the number of teeth is explained by the adaptation of animals to various food items. In carnivores, the number of teeth does not exceed 44, but in artiodactyls or rodents, the number of teeth varies greatly. Some edentates have 18–20 teeth; some species of marsupials can have up to 58 teeth, and representatives of the odontocetes of the dolphin family have 250 teeth. Teeth perform different functions in different orders of mammals and develop to varying degrees. So, for example, powerful canines develop in carnivores, incisors and molars develop in rodents, and canines and often premolars are lost. The function of mammalian teeth affected the nature of their attachment to the jaws and the characteristics of tooth replacement. Typically, mammalian teeth sit in the alveoli of the jaws and are strengthened by the connective tissue surrounding the teeth. In mammals, incisors, canines and premolars are replaced, and very rarely molars (in marsupials only the last molar changes). In edentate and toothed cetaceans, teeth do not change at all, and their milk teeth function throughout their lives. Only in elephants and manatees there is a constant longitudinal replacement of a worn tooth with a new one, which is laid behind the old one and gradually displaces it.

3. Human teeth, their number, classification. Changing teeth. (5 minutes)

Look at the slide, how many teeth does a person have?

Are they the same in appearance?

What are the functions of each type of teeth? How is their structure related to the functions they perform?

What do you know about baby teeth and wisdom teeth? (answers)

A person's first milk teeth appear at 6-9 months. Milk teeth have some features: they are smaller in size, have fewer tubercles and divergent roots, between which lie the rudiments of permanent teeth. The number of roots in primary and permanent teeth is the same. From the age of 6-7 years, teeth change. Their rudiments form at the roots of falling out teeth. They compress the roots of baby teeth and block the path of blood to them.

Why are wisdom teeth called that? (answers)

When a wisdom tooth begins to grow, it often does not have enough space in the existing row of teeth, which can cause complications. Improper tooth eruption can be accompanied by inflammatory diseases. When injured, infection can penetrate into the soft tissues surrounding the tooth. Inflammation can spread to deep tissues, causing periodontitis. Signs of inflammation are redness and swelling of the gums around the tooth, an unpleasant odor, and severe pain.

4. Tooth structure (3-4 minutes)

Read the textbook article on the structure of teeth, write down in your notebook the terms corresponding to the numbers on slide 11.

The tooth consists of dentin, the crown is covered with enamel, the neck and root are covered with cement. Dentin and cement are modified bone tissue.

Note to teacher: Checking the assignment of slide 11 is done by clicking on the numbers in the rectangles. The teacher's explanation for this slide is possible. As the explanation progresses, the necessary terms are gradually revealed.

5. Physical education: performing exercises while standing (stretching, etc.) to change position. (2 minutes)

5.Diseases and dental hygiene (12 minutes)

Remember from the 5th grade course what happens to rocks in the sun and frost. (answers)

5.1. Model experiment

Let's try to heat the glass in the flame of an alcohol lamp, and then lower it into water.

What happened to the glass and why?

Why can’t you immediately drink cold drinks or ice cream after a hot meal? (Tooth enamel can also crack from sudden changes in hot and cold foods. Protect your tooth enamel from sudden changes in temperature.)

5.2.Dental diseases

With dental disease, digestion is disrupted, since in this case food that is not chewed enough and unprepared for further chemical processing enters the stomach. This is why it is so important to constantly take care of your teeth. Nicotine released during smoking causes great harm to teeth and gums; Under no circumstances should you chew hard objects, and you should not drink cold water or eat ice cream immediately after eating hot food. This leads to the appearance of cracks in the enamel and caries (destruction of enamel and dentin). Bad breath appears, yellowing and destruction of enamel occurs, destruction of gum tissue around the teeth - periodontal disease. Caries is caused by bacterial plaque. Bacteria produce acid from sugar. Acid destroys tooth enamel and a “hole” is formed. Bacteria reach the pulp, affecting nerves and blood vessels. There is destruction of the pulp, inflammation of the tooth root and gum pocket. There is a danger of pus spreading throughout the body. Infection enters the body through a diseased tooth. Pathogenic microorganisms can cause inflammatory processes in the intestines, liver, etc.

5.3. Preventing tooth damage

Read the article “Healthy teeth are an important condition for maintaining human health” and make a memo for primary school students on what to do to maintain healthy teeth. Approximate rules: do not chew bones and hard candies; do not crack nuts; do not drink cold water or eat ice cream immediately after a hot meal; do not smoke, nicotine is harmful to teeth and gums; visit the dentist twice a year, etc.

5.2 Dental care

Note: By clicking on the image on slide 11 you can increase the size of the illustration. Hygiene rules can be scrolled through repeatedly by clicking on the button labeled “click”

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Slide captions:

Classification of bacteria - bacteria of decomposition and decay; - soil bacteria; - lactic acid bacteria; - pathogenic bacteria.

1. Bacteria of decomposition and decay The soil contains a huge number of bacteria - hundreds of millions per gram. In poor tundra soils or sandy desert soils there are up to a billion of them, in slightly podzolic soils - up to a billion, and in chernozem rich in organic matter - up to 2 billion and more. This is about 35 dry weight of the soil. Bacteria take part in the weathering of rocks and minerals. Thus, iron bacteria formed large deposits of iron ores.

2. Nitrogen-fixing (soil) bacteria NODULE BACTERIA - a genus of bacteria that form nodules on the roots of many leguminous plants and fix molecular nitrogen from the air in conditions of symbiosis with the plant. They enter into symbiosis with leguminous plants. Settling in the roots of legumes, they cause the formation of nodules on them, for which they received the name nodule bacteria. The plant supplies the bacteria with the carbohydrates and mineral salts they need for growth and development, and in return receives nitrogen, which the nodule bacteria are able to fix.

3. Lactic acid bacteria Lactic acid bacteria are involved in the creation of fermented milk products. Fermented milk products are a group of dairy products produced from whole cow's milk or its derivatives (cream, skim milk and whey) by fermentation with starter cultures. Lactic acid products are also made from the milk of sheep, goats, mares and other animals.

Fermented milk products - ayran; - acidophilus; -kefir; - yogurt; -ryazhenka; - Varenets; - kaymak; - curdled milk; -Koumiss.

Ayran A type of fermented milk drink based on katyk or a type of kefir among the Turkic and Caucasian peoples (in different languages ​​the exact meaning of the name and the preparation technology are slightly different, but the common thing is that it is a dairy product produced with the help of lactic acid bacteria).

Acidophilus is a dietary product - milk fermented with special (acidophilus) bacteria. It is produced from milk fermented with pure culture starters, one of which is acidophilus bacillus. In 1910, the Russian scientist Hartier E.E. proved that acidophilus bacillus can be successfully used for therapeutic and preventive purposes in the fight against gastrointestinal diseases, and that this bacterium cleanses the intestines of putrefactive and some pathogenic microbes.

Kefir Kefir is a fermented milk drink made from whole or skim cow's milk by fermented milk and alcohol fermentation using kefir “fungi” - a symbiosis of several types of microorganisms: lactic acid streptococci and rods, acetic acid bacteria and yeast

Yogurt Yogurt (a fermented milk product that is made from whole milk by fermenting it with special cultures - Lactobacillus bulgaricus (Bulgarian bacillus) and Streptococcus thermophilus (thermophilic streptococcus).

Ryazhenka Ryazhenka is a fermented milk drink made from baked cow's milk by combined lactic acid and alcohol fermentation. Fermentation is carried out with thermophilic lactic acid streptococci and pure cultures of Bulgarian bacillus, fermented for 3-6 hours. It has a yellowish-brownish tint and a traditional fermented milk taste. In fact, it is a type of unflavored yogurt.

Varenets Varenets. Baked milk, prepared by slowly melting (evaporating) milk in clay jars in a Russian oven so that it reduces by at least a third of its volume and acquires a reddish tint. To do this, milk is placed in the oven after the bread for several hours, during which it “dries out” but does not boil. Then the baked milk is seasoned (fermented) with sour cream (at the rate of 200 g per liter) and kept covered for 3-4 hours in a warm room.

Kaymak Kaymak - thick, thick, pancake-like, boiled foam, prepared from fatty baked milk. Milk for kaymak is boiled over low heat in a flat container and, as the foams thicken, they are removed and layered one on top of the other, then allowing them to sour slightly over the course of a day or two. Kaymak also has a special microflora created in it as a result of acid fermentation, which turns it not only into a pleasant, tasty, nutritious, but also into a healthy product, especially for those who find it difficult to tolerate ordinary fats.

Kumis Kumis is a whitish fermented milk drink made from mare's milk, obtained as a result of lactic and alcoholic fermentation using Bulgarian and acidophilic lactic acid rods and yeast.

Lactic acid bacteria are involved in the fermentation of cabbage and pickling of cucumbers and tomatoes.

Curdled milk Produced by lactic acid fermentation of milk

Cheeses Roquefort cheese is obtained as a result of the activity of lactic acid bacteria and special fungi

4. Pathogenic bacteria Cause diseases such as typhoid, dysentery, cholera, brucellosis, tuberculosis, sore throat, glanders, anthrax, tetanus, plague.

Pathogenic bacteria Staphylococcus aureus

Streptococcus and streptococcal infection

Vibrio cholerae

Fighting pathogenic bacteria Disease prevention measures: - close your mouth when coughing; - boil handkerchiefs; - exercise medical control over water sources and food products; - disinfect premises; - get preventive vaccinations.

The role of bacteria in nature and human life. Lesson objectives:

• 1.Study the role of bacteria in nature.
• 2.Study the role of bacteria in human life

• 1. The role of bacteria in nature.
• A. Bacteria of decomposition and putrefaction.
• B. Soil bacteria.
• 2. The role of bacteria in human life.
• A. Bacteria in human economic activity (lactic acid bacteria).
• B. Pathogenic bacteria.

• Bacteria of rotting and decomposition turn dead plants, animals and garbage that humans create into humus soil.
• Soil bacteria convert humus into minerals. Plants need minerals to grow.
• Nodule bacteria live in the soil on the roots of plants and enrich the soil with nitrogen, which plants need.
• Bacteria are involved in the creation of minerals on Earth.

• The earth would be covered in a pile of dead matter, and we would simply drown in it.
• If there were no bacteria, the minerals in the soil would be depleted. There would be no food for the plants.
• Plants would die and the oxygen in the atmosphere would run out.
• LIFE ON EARTH WOULD DISAPPEAR!

• Green card. I'm satisfied with the lesson. The lesson was useful for me. I worked usefully and well in the lesson.
• Yellow card. The lesson was useful to me to a certain extent. I completed a number of tasks. I felt quite comfortable in the lesson.
• Red card. I received little benefit from the lesson. I didn't really understand what they were talking about. I do not need it.

• Paragraph 12, answer questions 1 – 8.
• In the workbook: tasks No. 45, No. 47

“Exponent with a negative exponent” - Calculate: Solve the problem. Solve the equation. Follow the steps. A degree with a negative exponent. Simplify the expression:

“Division of negative numbers” - We need to repeat the division of negative numbers and numbers with different signs. Compare with zero. WELL DONE! Right. When dividing numbers with different signs, you get a negative answer. Guys! Remember! The absolute value of a number. Dividing two negative numbers results in a positive number. Find the quotient. So, let's summarize...

“Negative number” - What number is intended? Classwork. Writing negative numbers. If Zhu sells 200 yuan of rice now, he will earn 3 yuan per 1 yuan. Task. Rules for dealing with positive and negative numbers. The mathematician Diophantus used negative numbers in calculations. Solving equations. Lesion? The Ancient East.

“Fungi and Bacteria” - Prepare riddles about these groups of organisms. A crossword puzzle is drawn on the board. Lesson plan. "Auction". Goal: What disease agent is named after me? Lichens. Answer the questions. 1. Organizational moment. Questions from Robert Koch. Seaweed. Messages must be creative and accompanied by drawings.

“Negative numbers” - A complete and completely rigorous theory of negative numbers was created only in the 19th century (William Hamilton and Hermann Grassmann). Ancient Greek mathematician Diophantus. We think of negative numbers as something natural, but this was not always the case. Higher than nothing and lower than nothing. The first information about negative numbers was found among Chinese mathematicians in the second century BC.