I made a presentation on the topic of beneficial and harmful bacteria. Bacteria

Biology lesson 5th grade teacher Tsarapin A.N.

REMEMBER! 1.Which organisms do not have a body consisting of several cells? 2.What kingdoms of organisms are the living world divided into?

GOALS: 1. Study the structural features and vital functions of bacteria. 2. Show the role of bacteria in nature and human life

Bacteria - These are primitive unicellular organisms, in the cytoplasm of which there is no formed nucleus. The nuclear substance is distributed throughout the cytoplasm. Bacteriology - a branch of microbiology that deals with the study of bacteria.

? 1. What process underlies the increase in the number of bacteria? 2. How do you think bacteria can reproduce?

Nutrition of bacteria create themselves and also feed on ready-made nutrients.

4. Soil bacteria 5. Bacteria of decomposition and decay

1. Participate in the formation of soil structure and fertility 2. Formation of minerals 3. maintain reserves carbon dioxide and oxygen in the atmosphere

1. lactic acid bacteria

harmful bacteria to humans pathogenic bacteria

A1. Bacteria are organisms: 1. only unicellular; 2. only multicellular; 3. both unicellular and multicellular A2. A bacterial cell contains: 1. shell, cytoplasm, nucleus; 2. cytoplasm, nucleus, nucleic acid; 3. envelope, cytoplasm, nucleic acid

A3. Bacteria: 1. eat ready-made nutrients; 2. are able to create nutrients themselves; 3. 1 and 2 are true.

A4. Determine the correct statement. 1. Bacteria belong to the animal kingdom 2. bacteria belong to the fungal kingdom 3. Statements 1 and 2 are not correct

A5. Determine the correct statement. 1. All bacteria cause harm to other living organisms. 2. all bacteria benefit only humans. 3. Man uses bacteria to create some food products

Homework 1. § 11 page 44 of the textbook 2. optional write messages about human bacterial diseases and their prevention

Slide 1

Slide 2

Bacteria are prokaryotes. These are the simplest, smallest and most widespread organisms that have existed on earth for more than 2 billion years, but at the same time constantly evolving. Bacteria are so different from other living organisms that they are classified as a separate kingdom. There are not many places in the world that are free of bacteria. They live in water, soil, air, inside and on the surface of the bodies of animals and plants.

Slide 3

Slide 4

Slide 5

GROUPS OF REAL BACTERIA cocci (spherical) - single diplococci (collected in twos) streptococci (in the form of a chain)

Slide 6

staphylococci (in the form of a bunch of grapes) sarcina (in the form of dense packs) bacilli (rod-shaped)

Slide 7

convoluted - vibrios (comma-shaped) spirilla (one or more regular curls)

Slide 8

According to the method of nutrition, bacteria are divided into two groups: HETEROTROPHES (they are not able to synthesize organic matter, but feed on ready-made ones) AUTOTROPHES (able to synthesize organic substances from inorganic ones)

Slide 9

Slide 10

Most of bacteria can use almost any organic compound as an energy source, even substances used to destroy them (for example, penicillin, which kills many bacteria). This is due to the fact that bacteria can live both in the presence of oxygen in the environment and in its absence.

Slide 11

Bacteria are divided into two groups according to their feeding method: Anaerobic (decompose organic substances without the participation of oxygen) Aerobic (during the process of respiration they use oxygen to oxidize organic substances)

Slide 12

In relation to the development temperature, bacteria are also very diverse: some develop over a wide range of temperature changes, others - only at certain temperatures (low, high or in a narrow temperature range).

Slide 13

REPRODUCTION OF BACTERIA Bacterial cells, under favorable conditions, multiply very quickly, dividing in two. If a cell doubles every half hour, then it can produce 281474976710656 offspring per day. And some bacteria can multiply even faster.

Slide 14

The rapid proliferation of lactic acid bacteria in milk causes it to turn sour in a matter of hours.

Slide 15

Slide 16

Spore formation Under unfavorable conditions, for example, lack of water, many bacteria go into a dormant state. The cell loses water, shrinks somewhat and remains dormant until water appears again. Some species survive periods of drought, heat or cold in the form of spores. The formation of spores in bacteria is not a method of reproduction, since each cell produces only one spore and the total number of individuals does not increase.

Slide 17

When a spore forms, the cell shrinks, rounds within the existing cell wall and produces a new thick wall inside the old one. Under favorable conditions (humid conditions), the spore germinates. The spores are very resistant: they can withstand prolonged drying, boiling for several hours, and dry heating up to 140oC. Some spores can withstand temperatures of -245oC. They are also resistant to toxic substances and retain their viability. long time. Thus, anthrax bacilli remain viable, remaining in the form of spores for 30 years.

Slide 18

Survival of bacteria during drying Vibrio cholera up to 2 days Plague bacillus up to 8 days Diphtheria bacillus up to 30 days Typhoid bacillus up to 70 days Tuberculosis bacillus up to 90 days Staphylococcus bacillus up to 90 days

Slide 19

Positive value bacteria Determined by their participation in many biological processes, especially in the cycle of substances in nature. Bacteria, as a result of their vital activity, are able to decompose complex organic compounds into simple inorganic substances, which are again used by green plants. Bacteria are capable of decomposing proteins, carbohydrates, and fats.

Slide 20

A number of substances produced by bacteria as a result of metabolism are very valuable for humans. The activity of bacteria is used in various industries and Agriculture for the production of lactic acid products, for sauerkraut, forage silage, for the production of organic acids, alcohols, acetone, enzymatic preparations, etc. Man uses bacteria for processing Wastewater: When wastewater is slowly passed over gravel and sand, the solid particles settle and, under the action of various bacteria, are converted into a material that, after drying, is used as fertilizer. When passing through sand and gravel, pathogenic bacteria die and are digested by putrefactive bacteria.

Slide 23

Negative role of bacteria Pathogenic bacteria that cause diseases of plants, animals and humans play a negative role. Many saprophytic bacteria cause food spoilage, some of which are highly toxic. Toxins usually do not affect the body as a whole, but a specific organ or one of the organ systems - for example, the central nervous system, red blood cells, etc., causing a characteristic set of symptoms by which the disease can be diagnosed and its causative agent can be identified.

Slide 24

Of the plant diseases caused by bacteria, the following are known: burn that affects fruit plants - apple trees, pears, etc.; black rot of cabbage; soft rot of many plants; tumors of plant roots Despite the harm caused (bacterial root cancer); tumor-like growths on leaves (galls), etc.

1 slide

2 slide

3 slide

4 slide

BACTERIA Bacteria are prenuclear organisms, which we call microbes; they have a cellular structure. These are very ancient organisms that appeared on Earth about 3 billion years ago. The human eye first saw bacteria 300 years ago.

5 slide

It took another two hundred years before microbiology became an independent science. The new branch of biology gradually revealed the enormous role microorganisms play in human life, accompanying him from cradle to grave.

6 slide

ROLE OF BACTERIA Bacteria decompose dead organisms and restore conditions for the life of new creatures. Microorganisms are human helpers, enemies and companions in everyday life.

7 slide

The purpose of the work is to identify microorganisms that are companions of humans. To identify the dependence of the number of microorganisms on the operating mode of the school. Detect and count the number of microorganisms on the hands and objects of daily use of students.

8 slide

Description of the structure of microbes Bacteria are very small. They can only be seen under a microscope. Their body consists of only one cell. They are simpler than all other organisms – their cells don’t even have a nucleus.

Slide 9

Scientists know of at least 2,500 species of bacteria. They are found everywhere: in the air, in water, in soil, in the bodies of other living beings.

10 slide

Based on the shape and characteristics of the cell association, several groups of true bacteria are distinguished. Bacteria are simply structured and, in addition to the membrane and cytoplasm, they have hereditary material.

11 slide

The role of bacteria in nature The role of bacteria in nature is enormous - they are used to produce kefir, cheese, alcohols and citric acid. Many bacteria live in the body of plants - helping to absorb nitrogen from the air, others in the body of animals - help digest food, and still others are sources of various diseases.

12 slide

Slide 13

Materials and methods of research The research was carried out within the walls of our school. Air samples were taken in the school corridors and mathematics and biology classrooms, in addition, swabs were taken from the hands of primary schoolchildren, from the telephone receiver and from the pages of our textbooks.

Slide 14

To study bacteria, a medium was prepared: meat-peptin agar. (20 grams of agar-agar, 15 grams of meat broth, 500 grams of water were taken, all boiled, filtered and poured into sterile Petri dishes. The prepared dishes with the medium were used for experiments.

15 slide

To study the air, Petri dishes with the prepared sterile medium were opened for 15 minutes (according to the Koch and Clark-and-Gager method). Fingerprints (fingerprint method by V.N. Krylov, R.B. Goldin) were taken by lightly touching the fingers on a sterile nutrient medium.

16 slide

We examined: 1. The air in the classroom before lessons. 2. Air in the corridor on the 1st floor hanger after 4 lessons 3. Air in the classroom after evening cleaning

Slide 17

Condition of hand cleanliness - Swabs were taken from clean fingers - immediately after washing with laundry soap and an hour and a half after washing hands. Hand swabs of seventh graders after lunch

18 slide

Smears from a handset after long-term use from a handset, after treatment with alcohol Smears from the pages of an old textbook and pages of a new textbook

Slide 19

Then the results of the experiments were visually examined; the presence of bacteria was determined mainly by quantity, by counting the colonies that settled on the nutrient medium and calculated by the area of ​​the dish.

20 slide

To find out what could reduce the number of bacteria, a new culture of bacteria was done and tablets of chloramphenicol and tetracycline were placed on these cultures, and pieces of Kalanchoe leaves, fragrant geranium and drops of laundry soap were also used.

21 slides

EXPLORED - The air in the corridor with pills. levomitsitina The air in the corridor with drops of laundry soap The air in the classroom after lessons with Kalanchoe The air in the classroom after lessons with geranium.

22 slide

Research results Experiment results: the air environment at school is cleaner in the morning - 6 colonies. After 4 lessons the number of colonies became -13 After 7 lessons - 57 colonies

Slide 23

Bacteria in the air SAMPLE PLACE NUMBER OF BACTERIA COLONIES air in the classroom before lessons 6 air after 4 lessons 13 air after 7 lessons 57

24 slide

The result of swabs from fingerprints on the pages of books and a telephone. Clean fingerprints - 21 colonies. Fingerprints after 1 hour after washing - 23 colonies, and for a student after the cafeteria - 35 colonies. The result of an examination of the telephone handset and pages of books, you can see the results in the diagram

25 slide

26 slide

What did you find? Among the grown pure colonies of streptococci (STREPTOCOCCUS SALIVARUS), we distinguished staphylococci by color and examined them stained blue under a microscope with a magnification of 400 times

Slide 27

What helps to retard the growth of microbes The samples show that the tablets laid out on the culture media crops do not allow bacteria to develop - around tetracycline and levomycetin there is a clean nutrient medium (without bacteria) along the rim of 0.2 cm, pieces of leaves of fragrant geranium, Kalanchoe and a drop of soap foam., also inhibit the development of bacteria with a diameter of 0.1 to 0.5 cm.

Bacteria

A bacterium is a single organism that consists of a single cell and reproduces by division. The more favorable the habitat, the sooner it divides. These microorganisms live in all living things, as well as in water, food, rotten trees, and plants.

Actinomycetes are bacteria that cause the familiar smell of rain.

Despite the fact that sweets damage your teeth, chocolate is antibacterial and actually helps prevent tooth decay.

Tap water has a shelf life of 6 months because after that the chlorine begins to dissipate and bacteria multiply.

Some types of bacteria are also found in hairspray.

Dollar bills average approximately 3,000 various types bacteria.

In 2007, scientists revived 8 million year-old bacteria from Antarctic ice.

Every 20 minutes, new bacteria grows on your dishwasher.

In offices where there are more men than women, there are, on average, more bacteria.

There is a species of bacteria that is so resistant to radiation that scientists call it the “Conan Bacteria.”

There are absolutely no bacteria in the body of a newborn baby.

To use presentation previews, create an account for yourself ( account) Google and log in: https://accounts.google.com

Slide captions:

Plant cell What organelles of a plant cell do you know?

Bacteria

Bacteria are the oldest known organisms. Traces of bacterial activity belong to the Archean and date back to 3.5 billion years ago. The term "bacterium" comes from the Greek word "bacterion" - rod.

Bacteria can only be seen with a microscope, which is why they are called microorganisms or microbes; Microorganisms are studied by microbiology. The part of microbiology that studies bacteria is called bacteriology. This science was started by Anthony van Leeuwenhoek in the 17th century.

History of the study Bacteria were first seen through an optical microscope and described in 1676 by the Dutch naturalist Antonie van Leeuwenhoek. Like all microscopic creatures, he called them “animalcules.” The name “bacteria” was coined in 1828 by Christian Ehrenberg. In the 1850s, Louis Pasteur initiated the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties. Further development medical microbiology received in the works of Robert Koch, who formulated general principles determination of the causative agent of the disease (Koch's postulates). In 1905 he was awarded Nobel Prize for research on tuberculosis. The foundations of general microbiology and the study of the role of bacteria in nature were laid by M. V. Beyerinck and S. N. Vinogradsky. Microscope 1751

Bacterial cells are very small Bacteria are the smallest organisms that have cellular structure; their sizes range from 0.1 to 10 microns. A typical printing point can accommodate hundreds of thousands of medium-sized bacteria.

Compare plant and bacterial cells Plant cell Bacterial cell Write down features bacteria. Lack of a formed nucleus. Absence of large vacuoles with cell sap. Presence of organelles of movement (flagella and cilia) Presence of cytoplasm. The presence of a capsule around the shell.

According to their shape, bacteria are divided into several groups: cocci (have a round shape); bacilli (have a rod-shaped form); spirilla (have a spiral shape); vibrios (comma-shaped).

Methods of respiration of bacteria Aerobic – organisms need oxygen to oxidize organic substances. Anaerobic - Anaerobic organisms do not need oxygen, and for some species of this group it is even poisonous.

Reproduction of bacteria Bacterial cells under favorable conditions can divide into two every 20-30 minutes.

Formation of spores Under unfavorable conditions (lack of water, food, low temperatures) many bacteria enter a dormant spore state. The disputes are very persistent. They withstand heating, boiling, drying and low temperatures.

Diversity of bacteria Anthrax bacterium is the bacterium that causes tuberculosis. Cholera bacterium Lactic fermentation bacterium Diphtheria bacterium Staphylococcus bacterium

Check yourself. Test. 1. Bacteria belong to the following organisms: a) multicellular; 6) unicellular. 2. A bacterial cell includes: a) nucleus b) cytoplasm 3. The formation of spores in bacteria is necessary for: a) reproduction; b) experiencing unfavorable conditions. 4. Bacteria that use inorganic compounds to build organic substances are called: a) autotrophs; b) heterotrophs 5. Bacteria that have a rod-shaped form are called: a) spirilla b) bacilli