Job: Bacteria. Biology project on the topic "bacteria" Bacteria research work

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Purpose of the study: study the characteristics of the vital activity of bacteria; learn about diseases caused by bacteria and their prevention.

• study the available literature on the subject;
• analyze the effect of pathogenic bacteria on the human body;
• receive and summarize information from the infectious diseases doctor of Rospotrebnadzor about bacterial diseases in our area, their prevention.

Research methods:

• study of literature;
• collection of information;
• analysis of the collected information and systematization;
• presentation of results.

Lesson progress

Introduction.

In the 5th grade we started to study a new subject - biology. I was interested in the chapter “Bacteria Kingdom” and I had questions:

Why are bacteria, relatively simple microscopic single-celled organisms, so viable?

What conditions contribute to the spread of pathogenic bacteria and what preventive measures are in place?

Theoretical part

Bacteria were first seen through an optical microscope and described by the Dutch naturalist Anthony van Leeuwenhoek in 1676. Like all microscopic creatures, he called them "animalcules".

The name "bacteria" was coined by Christian Ehrenberg in 1828.

Louis Pasteur in the 1850s initiated the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties.

Medical microbiology was further developed in the works of Robert Koch, who formulated general principles definition of the causative agent of the disease (Koch's postulates). In 1905 he was awarded Nobel Prize for tuberculosis research.

The study of the structure of a bacterial cell began with the invention of the electron microscope in the 1930s.

The body of bacteria consists of a single cell. This cell is arranged completely differently than the cells of plants, animals and fungi. If their cells are separated by numerous partitions (membranes) into special compartments where the processes of respiration, nutrition, photosynthesis, etc. are carried out, then the “blocking” of bacteria is in its most rudimentary stage. The most important difference is that bacteria do not have a nucleus. Another difference is that there are no mitochondria and plastids. DNA in bacteria is located in the center of the cell, folded into a chromosome. If you “unroll” the DNA of a bacterium, its length will be about 1 mm.

Under favorable conditions, bacterial cells multiply very quickly, dividing in two. If a cell doubles every half an hour, then in a day it is able to give offspring. And some bacteria can multiply even faster.

And another one interesting ability bacteria. Under adverse conditions, they can often turn into spores. Such disputes remain alive for tens and hundreds of years, and in exceptional cases, even millions of years.

These features of bacteria allow them to survive in any conditions.

Depending on the shape of the cells, bacteria are divided into several groups: spherical - cocci, rod-shaped - bacilli or rods, spiral - spirilla, in the form of a comma - vibrios.

Human diseases caused by bacteria

Bacterial diseases are among the most common human diseases. Such diseases include some pneumonia (causative agent streptococcus), anthrax (causative agent - anthrax bacilli), cholera (causative agent Vibrio cholerae), tuberculosis (causative agent - tubercle bacillus (Koch's wand), plague (causative agent - plague bacillus) and others.

"Black Death" in ancient times and in the Middle Ages was called this disease, which inspired people with panic horror. In the VI century. the plague epidemic killed 100 million people. Some states, such as the Byzantine Empire, were almost completely depopulated.

From 1346 to 1351, 24 million people died from the plague (“great pestilence”, as they said then) - a quarter of the population of then Europe. With a story about the plague epidemic in 1348, the Italian Renaissance writer Giovanni Boccaccio begins his book “The Decameron”: people called them buboes. In a short time, this deadly tumor spread to other parts of the body, and then the symptom of this disease changed into black and purple spots that appeared on all parts of the body. It seemed that neither the doctor's advice nor the power of the medicine helped or benefited against this disease ... neither the wisdom nor the foresight of a person helped against it. Almost everyone died on the third day after the appearance of these signs.

In the XX century. plague epidemics practically ceased to threaten humans. Why did this happen? Of course, the systematic fight against this disease has played its role. Almost disappeared, displaced by the gray rat, the black rat, whose fleas served as carriers of the disease. But still, an exhaustive and accurate answer to the question of why the plague epidemics stopped has not yet been found.

Cholera is often compared to the plague because of its short duration and lethality. Cholera was brought to Europe only around 1816 from India, where it had been known since ancient times. In Russia, before 1917, more than 5 million people had been ill with cholera, and half of them died.

By the end of the XX century. epidemics of cholera have become quite rare thanks to prevention. We are currently living in the era of the 7th pandemic. For Russia, the problem remains relevant, the epidemic situation is assessed as unstable.

cholera prevention

Since cholera is “a disease of dirty hands”, it is necessary to wash your hands systematically before each meal, and in no case should you touch the mucous membranes of your mouth with unwashed hands. Wash hands only with hot water. Products must be kept in a place protected from flies and insects. Hygiene skills are the main weapon in the fight against cholera.

TUBERCULOSIS.

The ominous symptoms of pulmonary tuberculosis (consumption) - weakness, shortness of breath, and with advanced disease and hemoptysis - were familiar to the inhabitants of ancient Egypt and people who lived hundreds of thousands of years ago. This was shown by studies of their remains.
In antiquity and in the Middle Ages, there was a belief that crowned persons could cure tuberculosis with their touch. English King Charles II in the 17th century. touched more than 90 thousand patients. For the "treatment" a considerable fee was charged, which went to the royal treasury.

Only in the 19th century the first tuberculosis sanatoriums appeared. But the real fight against this disease began after the discovery of the tuberculosis bacterium by Robert Koch in 1882.

Tuberculosis has not been completely eradicated even today. In the former Soviet Union, prisons and camps have become breeding grounds for tuberculosis, where a significant proportion of prisoners become infected with the disease. Tuberculosis is a social infection. “The poorer the population, the more often it suffers from tuberculosis”

Prevention of tuberculosis

For newborns, BCG vaccination is essential. Further, according to the stage of their maturation, a mandatory (every 8-12 months) setting of the Mantoux reaction is carried out. It is desirable to choose a place of residence in dry, well-lit places. The apartment is systematically done wet cleaning and ventilation.

Ways of transmission of pathogenic bacteria

Airborne way;

Handshake;

Houseware;

contaminated water and food;

Carriers of diseases are rodents, fleas, ticks, lice, cattle.

The poet Vladimir Mayakovsky, who undertook any kind of propaganda work, even wrote a poetic explanation for a poster dedicated to the fight against cholera. : “Citizen!

Not to die from cholera
take such steps in advance.
Don't drink raw water.
Drink only boiled water.
Also, do not drink kvass on the street.
Boiling water is a lot of work.
To keep up with your kvass early,
they just cook it from the tap...”

How does a bacterial infection progress?

With the development of a bacterial infection one of the first symptoms will be fever. Fever is a protective reaction of the body, as body temperature up to 39 degrees stimulates the immune system. If the body temperature rises above 39 degrees, then it must be brought down with paracetamol or, indirectly, with antibiotics (a decrease in body temperature within 24-48 hours from the start of antibiotic therapy is a sign of a properly selected antibacterial drug).

Another manifestation of the bacterial infectious process is the intoxication syndrome. It is manifested by a deterioration in well-being, apathy, a decrease in mood, headaches, pain in muscles and joints, nausea, vomiting, and the like are possible. To relieve these symptoms, you need to drink plenty of warm water (at least 2 liters per day). Excess water will dilute the bacterial toxins, reducing their concentration, and also remove some of them in the urine.

These two signs of bacterial inflammation are universal to almost all infections. All other signs are due to the characteristics of a particular pathogen, their exotoxins and other factors of aggression.

Immunity- immunity of the body to a foreign agent, in particular, to bacteria.

Human immunity protects our body constantly and always.

Task and human immunity find and neutralize bacteria that have entered the body, as well as their toxins.

To prevent the disease, some bacterial diseases are vaccinated. At the same time, weakened pathogens or poisons secreted by them are introduced into the body of a healthy person. The body creates special substances that help the vaccinated person to quickly cope with pathogenic bacteria in the future.

Practical part

I must say that recently there has been a “crowding out” of bacterial infections by viral ones, but their significance does not cease to be relevant. So, for example, in the 90s, having “calmed down” that diphtheria was not registered, the percentage of those vaccinated against this infection decreased, as a result - an increase in the incidence, outbreaks of this infection with fatal outcomes that could have been avoided. Among bacterial infections, intestinal infections occupy a huge place:

• cholera
• typhoid fever
• dysentery
• salmonellosis.

Incidence of bacterial infections by country

№	Diseases	cases	The reasons	Prevention
1.	Cholera	1994 - Chechen Republic, 415 cases; 2005 - Rostov region; 2006 - Murmansk region; 2008 - Bashkiria; 2010 - Moscow.	Changing socio-economic conditions: refugees, tourism, pilgrims; worsening of the ecological situation poor water quality	- Improving water quality Cleaning, sewerage of populated areas; Strict supervision of the work of public catering, the quality of products, suspension of patients from work; Compliance with the rules of personal hygiene; Veterinary Animal Control
2.	Typhoid fever	Cases of infection are constantly recorded in Russia	Migration, unsatisfactory state of cleaning of populated areas; poor quality of water supply, catering
3.	Dysentery Salmonellosis		Non-compliance with the rules of personal hygiene, eating contaminated products
4.	Tuberculosis	AT last years the number of new cases is constantly growing	Social - poverty of the population	- Early immunization of newborns; Statement of the Mantoux reaction for all children; Fluorography (adult population)

What about bacterial infections in our area? What are their causes and prevention? I learned about this from a doctor - an infectious disease specialist of the territorial department of Rospotrebnadzor in the Valdai district of Guseva Natalya Tomovna.

Incidence of bacterial infections by region

Disease	2005		2006		2007		2008		2009		2010		2011			2012
																area		region
	abs	per 100 thousand	abs	per 100 thousand	abs	per 100 thousand	abs	per 100 thousand	abs	per 100 thousand	abs	per 100 thousand	abs	per 100 thousand	abs		per 100 thousand	abs
Dysentery	9	59,4	5	33,0	5	34,0	-	-	-	-	-	-	-	-	-		-
salmonellosis	-	-	-	-	2	13,7	-	-	-	-	-	-	3	23,7	1		8,0
Scarlet fever	1	6,6	-	-	15	103,2	3	20,6	7	49,2	4	28,7	-	-	1		8,0
Diphtheria	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-		-	7
Whooping cough	-	-	-	-	-	-	-	-	-	-	3	21,5	-	-	-		-	7221
meningococcal infection	1	6,6	-	-	-	-	-	-	-	-	1	7,2	-	-	1		8,0
Tuberculosis	9	59,4	3	19,8	7	48,1	9	61,9	10	70,3	11	79,0	4	31,6	3		24

The diagram shows that over the past 5 years, no cases of dysentery and diphtheria have been registered (although 7 cases were noted in the region in 2012). Meningococcal infection (there was 1 death), salmonellosis and scarlet fever are constantly recorded. But the most noticeable increase is the number of new cases of tuberculosis patients and the average number of annually registered patients in our region is 6-7 people.

Recently, there have been many parents who refuse to vaccinate their children, thereby exposing their children to mortal danger, as well as endangering other children. It is reliably known that a decrease in the incidence is possible only with a high level of immunization of the population - 99%, in 2012 this figure for all infections in our region decreased to 94%.

The implementation of this study allowed me to develop the skills of working with additional literature, the ability to conduct research, and substantiate the results of research.

During my research work, I came to the conclusion:

1) bacterial diseases are still one of the most common diseases;

2) to protect yourself from bacteria, you need to follow the rules of personal hygiene, do not eat unwashed fruits and vegetables, do not drink unboiled water, eat only fresh food, and, of course, do not forget to wash your hands more often.

3) an effective measure for the prevention of bacterial infections is the immunization of children and adults.

Practical value work consists in the fact that the materials obtained can be used in biology lessons when studying the topic “Bacteria” or during extracurricular activities.

LITERATURE

1. Borisov L.B. etc. Medical microbiology, virology, immunology. M.: Medicine, 1994.

2. Vasiliev K.G. Segal A.E. History of epidemics in Russia. Moscow: Medgiz, 1960.

3. Likum A. Children's encyclopedia "Everything about everything." M.: AST, 2008

4. Galpershtein L.Ya. My first encyclopedia. ROSMEN, 2007.

5. Children's encyclopedia "I know the world." The medicine. M.: Astrel, 2006.

6. Internet resources (illustrated materials for the presentation)

Research work Topic : Determination of contamination with spores of bacteria and fungi of different school premises

Job done :

Zharkova A., Petrunina D., Safoneeva V. students of the 10th grade.

MBOU secondary school №2

Lyskovo

Supervisor: Blinov A.E. biology teacher of the 1st category

different areas of the school

Research hypothesis .

• It is known that airing the room can reduce the level of bacterial air pollution, however, due to the cold winter, this possibility is limited.

2. It is also known that many houseplants have phytoncidal properties and can also reduce the number of microorganisms in the air.

3. It is possible to presumably include bacterial microorganisms, which can be opportunistic pathogens, and fungal organisms, which are allergens, in the composition of the air pool of the school.

choice of methodology, place of experiments and preparation of equipment; preparation and conduct of experiments; description and processing of the received data; conclusions." width="640"

Determination of bacterial and fungal spore contamination different areas of the school

aim This study was the study of the microflora of the air basin of school premises, as well as the study of the cleanliness of the hands of primary school students. In the course of the research, the quantitative and qualitative composition of the air microflora of school No. 2 and the cleanliness of hands were studied.

Based on this, tasks studies were as follows:

Choice of technique, place of experiments and preparation of equipment;

Preparation and conduct of experiments;

Description and processing of the received data;

Conclusions.

Determination of bacterial and fungal spore contamination different areas of the school

The urgency of the problem.

Microbes are ubiquitous throughout environment. Air is a medium containing a significant number of microorganisms. The largest number of microorganisms contains the air of industrial cities, the air of enclosed spaces with a large crowd of people.

At present, when the use of disinfectants and disinfectants has been sharply weakened, there is a spread of diseases that were considered defeated. Outbreaks and epidemics of bacterial and viral diseases often occur in children's and school groups: dysentery, diphtheria, typhoid fever, hepatitis and many others. This circumstance makes it necessary to strengthen the sanitary and environmental control of air, especially in children's and school premises, in order to improve its sanitary condition.

Method for preparing nutrient media for growing microorganisms.

For the cultivation of microorganisms, various nutrient media are used. This is necessary for the differentiation of infectious diseases, for the preparation of vaccines, antibiotics, etc.

The following requirements are imposed on nutrient media: they must contain all the necessary substances for the nutrition of microbes, have a certain reaction of the medium, be sterile and always moist. Nutrient media are divided into simple and complex.

Simple media include meat-peptone broth, meat-peptone agar, and meat-peptone gelatin (MPG). All simple nutrient media are prepared in meat water. For its preparation, the meat is separated from fat and fascia, crushed, poured with water in a ratio of 1: 2 and boiled for 30-60 minutes. Then it is filtered, topped up to the original volume and sterilized at a pressure of 0.1 MPa for 30 minutes.

Culture medium preparation

Dense gelatinous nutrient medium.

Ingredients: edible gelatin 30 g, Gallina Blanca chicken cube, fish, water 200 ml.

Cooking: pour gelatin into a glass of boiled water at room temperature, leave for 40 - 60 minutes. Boil fish - got fish broth. Dissolve chicken cube in fish broth, add gelatin and heat without boiling.

The method of sowing microorganisms on a nutrient medium

The method of sedimentation of dust particles containing spores of bacteria and fungi was used. Petri dishes were placed in various rooms of the school (canteen, recreation, toilet, hall in front of the entrance) and chaotic movements were made around these dishes (dust was raised) for 5 minutes.

Petri dishes were closed and placed in a dark cabinet.

The study of hand cleanliness in primary school students

Samples of fingerprints were taken on a nutrient medium from students elementary school(4 "B" class), Petri dishes are also placed in a dark cabinet.

Growing microorganisms

Growing microorganisms on a nutrient medium provides for the growth of these organisms for approximately 2 weeks to 2 months.

1st floor (recreation at the entrance)

Bacteria colony

Bacteria colony

Method for counting microorganisms

For quantitative accounting of microorganisms, such 3 dilutions are selected, when sown on a nutrient medium in a Petri dish, at least 50 and no more than 300 colonies grow. If few or many small colonies have grown, then they are counted with a magnifying glass, turning the cup upside down. If a large number of colonies have grown, then the bottom of the cup is divided into sectors, and counting is carried out in each sector. At very large numbers grown colonies use a special Wolfgügel counting chamber.

• Dining room - 6 large colonies of mold fungi;
• Recreation -3 large colonies of mold fungi;
• Hall - 1 large bacterial colony;
• Toilet colonies of bacteria and mold spores were not found.

• The first row is 10 bacterial colonies;
• Second row - 83 bacterial colonies;
• Third row - 54 bacterial colonies; 1 colony of fungi.

The most polluted room in the school is the canteen, and the cleanest is the bathroom. node. Why? Cleaning in the bathroom The unit is produced with a more concentrated solution of bleach (bleach), so contamination with spores of mold fungi and bacteria is minimal.

The school most visited by children is, of course, the dining room and buffet. It is because of this that it is the most polluted building in the school.

The cleanliness of the hands of children leaves much to be desired, on the hands of a large number of bacteria.

• Do a wet cleaning of the dining room more often.
• Use weak solutions of detergents and antiseptics.
• Carry out general cleaning of the premises at least 2 times a week.
• Ventilate rooms more often.
• Students must practice personal hygiene.
• Wash hands not only before eating, but also in the intervals between training sessions (after 2, 3 sessions).

Maslov Arseniy

Research work of a 3rd grade student on the topic "Bacteria: harmful and beneficial."

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Relevance… Once I asked my parents why people get sick? Mom said that bacteria enter the body and the person gets sick. And then I thought, what are bacteria, where do they live, how do they reproduce and why are they dangerous? And are all bacteria harmful? The purpose of the study: to study the characteristics of the life of bacteria and find out whether they can be beneficial and harmful. Tasks: to study the literature on the chosen topic, to get acquainted with the diversity and classification of bacteria, to find out what are the harmful and beneficial bacteria, to prepare homemade kefir

Object and subject of study Object of study: bacteria Subject of study: the importance of bacteria for humans Hypothesis Hypothesis: suppose that many bacteria live in the human body, they are both beneficial and harmful, and they can be propagated at home. Research methods: Working with additional sources, searching for the necessary information; Observations and analysis of the received information; Experiences; Test; Data processing

The History of Bacteria Bacteria were first seen through an optical microscope and described in 1676 by the Dutch naturalist Anthony van Leeuwenhoek. The name "bacteria" was coined in 1828 by Christian Ehrenberg. The study of bacteria and their structure is carried out by microbiology, which was formed in the second half of the 19th century as the science of pathogens, that is, as a branch of medicine. It is difficult to find a place on Earth where there would be no bacteria. They are found in a wide variety of places: in the atmosphere and at the bottom of the oceans, in fast-flowing rivers and in permafrost, in fresh milk and in nuclear reactors; however, especially a lot of them in the soil

The structure of bacteria A bacterium has a complex structure. The cell wall protects a unicellular organism from external influences, gives a certain shape, provides nutrition and preserves its internal contents. The plasma membrane contains enzymes, participates in the process of reproduction, biosynthesis of components. Flagella are called surface structures that serve to move cells in a liquid medium or on a solid surface. Cytoplasm serves to perform vital functions. In many species, the cytoplasm contains DNA, ribosomes, and various granules. Pili are filamentous formations, much thinner and smaller than flagella. They are of various types, differ in purpose, structure. Pili are needed to attach the body to the affected cell.

Types of bacteria cocci (have a rounded shape); bacilli (have a rod-shaped form); spirilla (have the shape of a spiral); spirilla (have the shape of a spiral);

Classification of bacteria Beneficial bacteria Escherichia coli It is an integral part of the intestinal flora of humans and most animals. Its benefits can hardly be overestimated: it breaks down indigestible monosaccharides, promoting digestion; prevents the development of pathogenic and pathogenic microorganisms in the intestine. Lactic acid bacteria Representatives of this order are present in milk, dairy and fermented products, and at the same time are part of the microflora of the intestines and oral cavity. Able to ferment carbohydrates and in particular lactose and produce lactic acid, which is the main source of carbohydrates for humans. By maintaining a constantly acidic environment, the growth of unfavorable bacteria is inhibited. Bifidobacteria Through the production of lactic and acetic acids, they completely prevent the development of putrefactive and pathogenic microbes in the child's body. In addition, bifidobacteria: contribute to the digestion of carbohydrates; protect the intestinal barrier from the penetration of microbes and toxins into the internal environment of the body

Harmful bacteria Salmonella This bacterium is the causative agent of a very acute intestinal infection, typhoid fever. Salmonella produces toxins that are dangerous only for humans. Tetanus bacillus This bacterium is one of the most persistent and at the same time the most dangerous in the world. Produces an extremely toxic poison, tetanus exotoxin, leading to almost complete damage to the nervous system. Mycobacteria Mycobacteria are a family of bacteria, some of which are pathogenic. Various representatives of this family cause such dangerous diseases as tuberculosis, mycobacteriosis, leprosy (leprosy) - they are all transmitted by airborne droplets.

My experiences… Making homemade kefir

Cultivation of hay stick Among the bacteria that are widespread in nature, hay stick is also included. It was first described in 1835. And it got its name due to the fact that initially the culture was isolated from rotten hay. This bacterium is one of the largest. It has a straight elongated shape with blunt rounded ends and is usually colorless. This bacterium is quite easy to obtain at home. For work, I needed the following: hay (you can buy it at a pet store), a pot of water, a jar with a wide neck, gauze for filtering. For one liter of water you need to take 10 grams of hay. Boil the hay for 20 minutes. The resulting broth is filtered and poured into a jar, diluted 1: 1 with settled cold water. In another jar, I decided to pour undiluted broth and see what happens. Banks put in a warm place. The best conditions for the life of hay sticks are a large amount of dissolved organic substances, an abundance of oxygen and a temperature of about +30 degrees. Under such conditions, a film consisting entirely of bacteria should form on the surface of the hay decoction in two days.

The results of the "Bacteria" test It turned out that many guys do not know about the kingdom of bacteria and the existence of beneficial bacteria in our dairy products.

Conclusion By studying bacteria, I got acquainted with their diversity and classification, I was able to grow bacteria on my own at home. I learned that there is a huge amount of beneficial bacteria that we consume every day with fermented milk products and about harmful bacteria(dangerous to humans) I found out that bacteria are an indispensable part of our life and all living things. They are absolutely everywhere and in everything, play a colossal role in human life. People have learned to use bacteria: Based on the above material and the research, I believe that my hypothesis was confirmed: “Many bacteria live in the human body, they are both beneficial and harmful and they can be propagated at home”

City open competition

research and creative projects

junior schoolchildren

"WHAT? WHERE? WHY?"

Nomination: "Human health and its protection"

Job title:"Bacteria in human life"

Work completed: Yulia Pozhidaeva

Place of execution: Cherkessk

MKOU secondary school No. 4, 4 "A" class

Supervisor: Makletsova L.P.

CHERKESSK 2014

Introduction.

Main part:

1. What is bacteria?

2. Forms of bacterial cells.

3. The role of bacteria in human life.

4. Microbiological research.

Conclusion.

Bibliography.

Annex (presentation "Bacteria in human life")

Introduction.

Our planet Earth is inhabited by a variety of living organisms. I'm interested in bacteria. From the lessons of the world around me, I learned that bacteria can live in soil, water, air, on the human body and even inside it. We often hear "Dirty hands are the source of disease." I decided to explore what kind of bacteria "live" on our palms, and how they can affect our health. To do the research, I needed to know:

1. What are bacteria.

2. Study the shapes of bacterial cells.

3. To study the role of bacteria in human life.

4. Conduct a microbiological study.

To conduct the study, I turned to my classmates for help, they agreed to take swabs from their hands. And also my aunt, who works in the laboratory, helped me. In addition, it was necessary to study some articles in the encyclopedia and find the necessary information on the Internet.

Main part.

What is bacteria?

You've all heard that bacteria live on hands. But what are these "tenants" whom we did not invite? It is interesting to see them with your own eyes and count how many there are.

Bacteria are the simplest, smallest and most widespread organisms that have existed on earth for more than 2 billion years. Bacteria are so different from other living organisms that they are isolated in a separate kingdom. There are not many places in the world that are devoid of bacteria. They live in water, soil, air, inside and on the surface of the bodies of animals and plants.

2. Forms of bacterial cells.

In laboratories, bacteria are grown on a special nutrient medium. Millions of bacteria form colonies of various colors and shapes. Bacteria are divided into several groups according to their shape.

Some bacteria are spherical and are called cocci. From cocci, a chain is formed - streptococcus.

Under multiple magnification of the microscope, you can see beautiful clusters of cocci. This is a very dangerous staphylococcus. Bacilli having a rod-shaped form are very widespread.

If a bacterium looks like a comma or a curved rod, then it is called a vibrio.

There are also spirillae. Spirilla are similar to vibrios, but longer and slightly squirming.

3. The role of bacteria in human life.

From the course of the world around us, we know that there are harmful and beneficial bacteria.

If bacteria get into milk, they can cook us many different foods.

If we "invite" them to cook cabbage, then the cabbage will turn out to be sauerkraut.

In addition, E. coli bacteria live in our intestines and help digest food.

I was able to find out what bacteria are used:

For the production of medical products.

For agricultural pest control.

For wastewater treatment.

But there are also bacteria that spoil food, so food is stored in the refrigerator, salted and marinated.

Some types of bacteria cause serious diseases in humans, animals, and plants. I learned that disease and putrefaction bacteria produce poisonous substances that can poison the human or animal body.

4. Microbiological research.

Adults say: “Wash your hands,” but children listen to them and do it their own way.

I decided to conduct an experiment in the classroom and prove to my classmates that harmful microbes live on their hands.

I brought sterile test tubes with 10 milliliters of distilled water and swabs in them from the laboratory to the school. I moistened a cotton swab and made lavages, wiping the surfaces of both hands. After taking the sample, the swab was placed in a test tube and taken to the microbiological laboratory. There, my aunt seeded the samples on Petri dishes with a special nutrient solution, and then put them in a thermostat at a temperature of 37 degrees. After 48 hours, I counted the colonies of microorganisms. In order to see the microorganisms living on the hands, we were given smear preparations. We examined these smears under a microscope and determined the shape of the microbes and their number.

Research results.

students

Total Microbial Count (CFU/ml)

Comparison in %

unwashed hands

Hands washed with soap

Dima

Masha

Alina

Zhenya

According to the results in the table, we see that colonies of cocci, rods and molds were found in the swabs from dirty hands. And after thorough washing of hands with soap, the number of bacteria decreased by about half.

Conclusion.

Based on my research, I have developed memo:

It is necessary to wash your hands before eating, after coming from the street, after communicating with animals, as a lot of bacteria accumulate on them.

It is necessary to observe personal hygiene, as dirty hands are one of the easy ways for bacteria to enter our body.

Wash fruits and vegetables before eating.

Monitor product expiration dates.

During epidemics, limit contact with possible carriers of infections.

And I also want to introduce you to some interesting facts on the topic of my work:

Total weight bacteria living in the human body is two kilograms.

There are about 40,000 bacteria in the human mouth.

By the end of the first day of life, 12 types of bacteria live in the body of a newborn child.

I hope my research will help some guys to remember the rules of personal hygiene more often. Thank you for your attention.

Bibliography:

• Encyclopedia "Living World". Publishing house "Rosmen" 1995

  Encyclopedia "History of discoveries". Publishing house "Rosmen" 2003

  Encyclopedia "Secrets of wildlife". Publishing house "Rosmen" 2000

  The world. Auth. T. Ivchenkova.

  Internet resources.

The text of the work is placed without images and formulas.
Full version work is available in the "Files of work" tab in PDF format

annotation

Vasyankina Nina

Kulebaksky district, r.p. Gremyachevo, MBOU Gremyachevsky secondary school, 7 b "Amazing bacteria".

Leader: Drews Svetlana Andreevna, biology teacher. MBOU Gremyachevskaya school №1

Target scientific work: study of the features of the structure and vital activity of bacteria, determination of their positive and negative impact on human life, conduct laboratory work to detect bacteria.

Conducting method: abstract-research with practical work. The main results of the study: studied in detail the structure and vital activity of bacteria; determined the importance of bacteria in the biosphere and national economy; spent practical work on the detection of lactic acid bacteria, decay bacteria, studied their properties; found out Interesting Facts about bacteria.

Introduction………………………………………………………………………………….4

Main part:

Discovery of a bacterial cell…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………5

The structure and vital activity of bacteria……………………………………………..... 7

The importance of bacteria in the biosphere and the national economy…………………………..….10

Practical work “Detection of lactic acid bacteria, study of their properties”…………………………………………………………………………………..13

Interesting facts about bacteria…………………………………………………………………………16

Conclusion…………………………………………………………………………………..17

Conclusion……………………………………………………………………………….19

References…………………………………………………………………....20

Introduction

Chosen theme of the work "Amazing bacteria)" relevant, as much attention is currently paid to the study of microorganisms - bacteria and viruses, their impact on the human body. Scientists around the world are working to develop drugs against many infectious diseases.

Working on this topic, I set myself the following goal: study of the features of the structure and vital activity of bacteria, determination of their positive and negative impact on human vital activity.

To achieve this goal, I set myself the following tasks:

to study in detail the structure and vital activity of bacteria;

determine the importance of bacteria in the biosphere and the national economy;

to carry out practical work on the detection of lactic acid bacteria, putrefaction bacteria, to study their properties;

learn interesting facts about bacteria.

II. Main part

1. Discovery of a bacterial cell.

Bacteriology is the branch of microbiology that deals with the study of bacteria. Bacteria along with were among the first living organisms on Earth, appearing about 3.5 billion years ago.

Bacteria (dr. Greek - stick) - the kingdom of microorganisms, most often unicellular. Currently, about ten thousand species of bacteria have been described, and it is estimated that there are over a million of them.

Bacteria were first seen through an optical microscope and described in 1676 by the Dutch naturalist Anthony van Leeuwenhoek. Like all microscopic creatures, he called them "animalcules".

The name "bacteria" was introduced by Christian Ehrenberg in 1828. Louis Pasteur in the 1850s initiated the study of the physiology and metabolism of bacteria, and also discovered their pathogenic properties.

Until the 19th century, microbiology was a collection of disparate facts. The founders of microbiology as a science were the outstanding scientists of the 19th century, the French chemist L. Pasteur (1822-1895) and the Russian botanist L. S. Tsenkovsky (1822-1887). In 1862, Pasteur brilliantly proved that microorganisms do not arise spontaneously. He proved that contagious diseases are caused by various microbes. Pasteur prepared vaccines against rabies and anthrax. Tsenkovsky L.S. showed the proximity of bacteria with blue-green algae.

The development of methods for growing microbes on various solid nutrient media is associated with the name of the German physician R. Koch (1843-1910), who discovered the anthrax bacillus, vibrio cholerae, and tubercle bacillus. After the work of L. Pasteur and R. Koch, microbiology was divided into a number of narrower specialties. There are general, agricultural, technical, veterinary and medical microbiology.

The works of S. N. Vinogradsky and V. L. Omelyansky played an important role in the development of general and soil microbiology. S. N. Vinogradsky established the fact of the assimilation of carbon dioxide by non-chlorophyll microorganisms, i.e., the ability to build one’s body entirely through the assimilation of inorganic substances. He proved the existence of anaerobic nitrogen-fixing bacteria; laid the foundation for the study of microorganisms inhabiting the soil. VL Omelyansky revealed the microbiological nature of the process of anaerobic decomposition of fiber. Of the researchers in the field of medical microbiology, D.K. Zabolotny, known for his work on the study of cholera and plague pathogens, should be noted.

Soviet microbiologists have done much to develop measures to prevent infectious diseases. Much has been done in the field of studying questions of general microbiology and in the application of microorganisms in industry and agriculture. Microbes are widely used to obtain alcohol, acetone, citric acid, yeast, to obtain antibiotics. In agriculture, bacterial fertilizers are used to increase crop yields.

Main part

2. The structure and vital activity of bacteria.

Bacteria - These are the smallest prokaryotic organisms that have a cellular structure. Due to the microscopic size of cells from 0.1 to 10-30 microns, bacteria

According to the shape and features of cell association, several morphological groups of bacteria are distinguished: spherical (cocci), straight rod-shaped (bacilli), curved (vibrios), spirally curved (spirilla), etc. Cocci linked in pairs are called diplococci, connected in the form of a chain - streptococci, in the form of clusters - staphylococci, etc. Filamentous forms are less common.

Cell structure. The cell wall gives the bacterial cell a certain shape, protects its contents from the effects of adverse environmental conditions, and performs a number of other functions. The basis of the cell wall of bacteria (as well as all prokaryotes) is a special substance - murein (a polysaccharide combined with several amino acids). Many types of bacteria are surrounded by a mucous capsule, which serves as an additional protection for the cells.

The arrangement of the flagella is one of the characteristic features in the classification of motile forms of bacteria.

The plasma membrane does not differ in structure and function from the membrane of a eukaryotic cell. In some bacteria, the plasmalemma is able to form invaginations into the cytoplasm, called mesosomes. Redox enzymes are located on the folded membranes of mesosomes, and in photosynthetic bacteria they also have the corresponding pigments (including bacteriochlorophyll), due to which mesosomes are able to perform the functions of mitochondria, chloroplasts and other organelles, as well as participate in nitrogen fixation.

In the cytoplasm there are about 20 thousand ribosomes and one large circular double-stranded DNA molecule, the length of which is 700 or a thousand times the length of the cell itself. In addition, most types of bacteria in the cytoplasm also have small circular DNA molecules called plasmids. Membrane structures (organelles) characteristic of eukaryotic cells are absent in bacteria.

A number of water and soil bacteria lacking flagella have gas vacuoles in the cytoplasm. By regulating the amount of gas in vacuoles, aquatic bacteria can sink into the water column or rise to its surface, while soil bacteria can move in soil capillaries. Spare substances of a bacterial cell are polysaccharides (starch, glycogen), fats, polyphosphates, sulfur.

Forms of a bacterial cell.

spherical kinds - cocci. AT form spirals - spirilla. rod-shaped bacteria - bacilli.

Nutrition of bacteria.

Bacteria are divided into two groups according to the type of nutrition: autotrophic and heterotrophic. Autotrophic bacteria synthesize organic substances from inorganic ones. Depending on what energy autotrophs use to synthesize organic substances, photo- (green and purple sulfur bacteria) and chemosynthetic bacteria (nitrifying, iron bacteria, colorless sulfur bacteria, etc.) are distinguished. Heterotrophic bacteria feed on ready-made organic matter of dead remains: (saprotrophs) or living plants, animals and humans (symbionts).

Saprotrophs include decay and fermentation bacteria. The first break down nitrogen-containing compounds, the second - carbon-containing. In both cases, the energy necessary for their life activity is released.

Reproduction. Bacteria reproduce by simple binary cell division. This is preceded by self-doubling (replication) of the DNA molecule. Budding occurs as an exception.

With the formation of spores in a bacterial cell, the amount of free water decreases, enzymatic activity decreases, the protoplast shrinks and becomes covered with a very dense shell. Spores provide the ability to endure adverse conditions. They withstand prolonged drying, heating above 100°C and cooling to almost absolute zero. In the normal state, the bacteria are unstable when dried, exposed to direct sunlight, when the temperature rises to 65-80°C, etc.; Under favorable conditions, the spores swell, forming a new bacterial cell.

Despite the constant death of bacteria (eating them by protozoa, exposure to high and low temperatures, and other unfavorable factors), these primitive organisms have been preserved since ancient times due to the ability to rapidly reproduce (a cell can divide every 20–30 minutes), form spores, and are extremely resistant to environmental factors, and their ubiquitous distribution.

cyanobacteria.

We will get acquainted with bacteria - "herbs". A little bit of moisture, air and sun - that's almost all they need to live. Yes, and these bacteria do not look quite normal. So unusual, in fact, that scientists have long considered them to be… algae! But studies have shown that these "algae" do not have a nucleus, and therefore, they must be attributed to bacteria - prokaryotes. Because of their blue-green color, they are called cyanobacteria (cyanus is Greek for "blue").

Cyanobacteria live in the most various places. Imagine a barren rock. Day after day they “bite off” the smallest grains from the stone. The stone is covered with cracks, into which the roots of the plant can launch, and eventually crumble into grains of sand. And the beginning of this was laid by cyanobacteria.

Do you have an aquarium in bloom? Did dark green flakes appear in it or plaque on the walls? Warning sign! Cyanobacteria appeared in the aquarium. Some cyanobacteria release substances poisonous to fish into the water. The processes of photosynthesis in cyanobacteria and eukaryotic organisms are carried out in a similar way. Their main storage carbohydrate is glycogen.

3. The importance of bacteria in the biosphere and the national economy.

The role of bacteria in the biosphere is great. Due to their vital activity, the decomposition and mineralization of organic matter of dead plants and animals occurs. The resulting simple inorganic compounds (ammonia, hydrogen sulfide, carbon dioxide, etc.) are involved in the general circulation of substances, without which life on Earth would be impossible. Bacteria, together with fungi and lichens, destroy rocks, thereby participating in initial stages soil-forming processes.

A special role in nature is played by bacteria that are able to bind free molecular nitrogen, which is inaccessible to higher plants. This group includes free-living Azotobacter and nodule bacteria that settle on the roots of leguminous plants. Penetrating through the root hair into the root, they cause a strong growth of root cells, which has the form of nodules. At first, bacteria live at the expense of the plant, and then they begin to fix nitrogen, followed by the formation of ammonia, and from it - nitrites and nitrates. The resulting nitrogenous substances are sufficient for both bacteria and plants. In addition, part of the nitrites and nitrates is released into the soil, increasing its fertility. The amount of nitrogen fixed by nodule bacteria can reach 450–550 kg/ha per year.

Bacteria play a positive role in human economic activity. Lactic acid bacteria are used in the preparation of a variety of dairy products (sour cream, curdled milk, butter, cheese, etc.). They also help preserve food. Bacteria are widely used in modern biotechnology for the industrial production of lactic, butyric, acetic and propionic acids, acetone, butyl alcohol, etc. In the process of their vital activity, biologically active substances are formed - antibiotics, vitamins, amino acids. Finally, bacteria are the object of research in the field of genetics, biochemistry, biophysics, space biology, etc.

The negative role belongs to pathogenic or pathogenic bacteria. They are able to penetrate into the tissues of plants, animals and humans and release substances that depress defensive forces organism. Such pathogenic bacteria as the causative agent of plague, tularemia, anthrax, pneumococci in animals and humans are resistant to phagocytosis and antibodies. A number of other human diseases of bacterial origin are known, which are transmitted by airborne droplets (bacterial pneumonia, tuberculosis, whooping cough), through food and water (typhoid fever, dysentery, brucellosis, cholera), through sexual contact (gonorrhea, syphilis, etc.) .

Bacteria can also infect plants, causing them so-called bacterioses (spotting, wilting, burns, wet rot, tumors, etc.). Bacterioses are quite common in potatoes, tomatoes, cabbage, cucumbers, beets, legumes, and fruit trees.

Saprotrophic bacteria cause food spoilage. In this case, along with the release of carbon dioxide, ammonia and energy, the excess of which causes heating of the substrate (for example, manure, wet hay and grain) up to its self-ignition, the formation of toxic substances also occurs. Therefore, in order to prevent spoilage of food products, a person creates conditions under which bacteria largely lose their ability to rapidly multiply, and sometimes die.

Lactobacilli and bifidobacteria live in the human body. They appear in our body from the first infancy and remain in it forever, complementing each other and solving serious problems. Lactobacilli and bifidobacteria enter into complex reactions with other microorganisms, easily suppress putrefactive and pathogenic microbes. As a result, lactic acid is formed, hydrogen peroxide - these are natural internal antibiotics. Thus, lactobacilli raise, restore the body's defenses and strengthen the immune system.

The beneficial functions of lactobacilli were first noticed by the Russian scientist Ilya Ilyich Mechnikov. The idea to use fermented milk products to normalize biochemical processes in the intestines and nourish the body as a whole belongs to him.

Bacteria cause food spoilage. Therefore, in order to prevent spoilage of food products, a person creates conditions under which bacteria largely lose their ability to rapidly multiply, and sometimes die. widespread fighting methods with bacteria are: drying of fruits, mushrooms, meat, fish, grains; their cooling and freezing in refrigerators and glaciers; pickling products in acetic acid; salting. When pickling cucumbers, tomatoes, mushrooms, sauerkraut due to the activity of lactic acid bacteria, an acidic environment is created that inhibits the development of bacteria. This is the basis of food preservation. The method is used to kill bacteria and preserve food. pasteurization—heating to 65°C for 10-20 min and sterilization method — boiling. Heat causes the death of all bacterial cells. In addition, in medicine, the food industry, and agriculture, iodine, hydrogen peroxide, boric acid, potassium permanganate, alcohol, formalin, and other inorganic and organic substances are used for disinfection, i.e., to destroy pathogenic bacteria.

Having studied various sources, I was convinced that all the materials confirm the hypothesis of my project that bacteria can be both harmful to humans and beneficial.

Practical work

Mini study

Having received information that bacteria are harmful and beneficial, it became interesting for me to look at them. To do this, I decided to conduct an experiment.

Description of the experiment.

In order to create a breeding ground for bacteria, I took a pot, put it on the stove and brought water to a boil. I added a bouillon cube and a spoonful of sugar to the water. Boil this mixture for a few minutes. She took the saucepan off the heat and let it cool. I brought the broth to class. I poured the same amount of broth into each of the previously prepared vessels. Then she coughed into one of the vessels, put her finger into the other, and did not touch the third vessel.

Sticker "Do not drink!" on each vessel she warned everyone that an experiment was underway. I wrapped the vessels in plastic wrap and put them in a warm place so that they would not interfere with anyone.

After a while, I checked what was happening with the broth. The liquid in the vessels became cloudy and began to emit an unpleasant odor, which is confirmation that there are bacteria in it.

After that, I took a few drops of liquid and tried to examine the bacteria with a magnifying glass. But this did not lead to a positive result - I did not see bacteria. Then I decided to resort to the help of another device - a light microscope.

At 200x magnification, I was able to see the bacteria in all the containers. I noticed that most of the bacteria were in the vessel into which I dipped my finger. This once again confirms the fact that bacteria live on our hands. And the least bacteria was in the third vessel. I would like to note that I was surprised by the small amount of bacteria in all containers, although they were in a warm place for several weeks. I think this is due to the presence of preservatives (substances that allow food not to spoil for a long time) in the bouillon cube.

"Detection of lactic acid bacteria, and the study of their properties"

For the first time, the benefits of fermented milk products were discussed at the beginning of the 20th century, when Ilya Mechnikov (Russian biologist, Nobel Prize winner) told the world about the favorable properties of this product. In the course of his research, Mechnikov found that in our gastrointestinal tract, as well as in fermented milk products, live microorganisms contain. They help the stomach to function successfully.

Target: to detect lactic acid bacteria, to study their properties.

Equipment and materials: microscope, slides, cover slips, test tubes, kefir, curdled milk, rotten potatoes, alcohol, methyl blue.

Progress.

Researching dairy products. To do this, you need to prepare smears of yogurt, kefir. I pour alcohol on an air-dry smear and hold for 1-2 minutes.

I paint with methylene blue. I examine preparations with an immersion lens. In a smear from curdled milk, diplococci will be visible, in kefir, sticks and yeast.

Experience 1. Spoilage of milk by putrefactive microbes. I add a few drops of liquid from a rotten potato to a test tube with milk and leave it in a warm place for 10-12 hours. As a result of the development of putrefactive bacteria, the milk protein will begin to dissolve and in 1-2 days it will completely dissolve with the release of foul-smelling gases.

Experience 2. Protection of milk from spoilage by lactic acid bacteria. I put putrefactive and lactic acid bacteria into a test tube with milk. As a source of lactic acid bacteria, you can take 1-2 ml of kefir. The development of lactic acid bacteria ensures the formation of lactic acid in milk, which inhibits the development of putrefactive bacteria. In a test tube, a normal clot of milk is obtained.

Conclusion: Dairy products contain three main types of beneficial bacteria: bifidobacteria, lactobacilli and enterobacteria. When we are healthy, the intestinal microflora includes probiotic lactic acid bacteria. It is precisely thanks to their work that all other microorganisms living in our gastrointestinal tract manage not only to coexist peacefully with each other, but also to work effectively for our benefit.

Conducting a survey

After I got acquainted with the information about bacteria and conducted my own mini-study, I became interested to find out how much the guys who study with me own this information.

To this end, together with the class teacher, we compiled a survey questionnaire. We interviewed 24 students in our class.

The survey included questions about bacteria and their importance in human life (see Appendix)

After analyzing the results, I found out that:

know about the existence of bacteria - 100% of students;

know that bacteria can cause various human diseases - 100% of students;

95.8% of students know that not all bacteria are harmful to humans;

100% i.e. all students know that bacteria live in the human body, 75% believe that they help digest food and restore the body's defenses;

many guys know that a person uses bacteria in economic activities.

Interesting facts about bacteria.

Scientists have discovered the packaging structure of light-sensitive molecules in green bacteria that helps organisms extremely efficiently convert sunlight into the chemical energy they need to live. The discovery may lead to the creation of a new generation of solar cells in the future, according to the authors of a study published in the journal Proceedings of the National Academy of Sciences.

The green bacteria studied by scientists use the energy of light to process sulfur or iron compounds, similar to how plants use sunlight in photosynthesis. At the same time, organisms are forced to be content with a very limited amount of sunlight, as they live in the waters of hot hydrothermal springs or in seas at a depth of more than 100 meters.

Japanese experts have created the world's first micromotor, which is powered by bacteria. Its main rotating component has a diameter of 20 millionths of a meter.

Bacteria and bacillus are one and the same. The first word is of Greek origin, and the second is of Latin origin.

There are bacteria that help clean your teeth. Scientists at the Swedish Karolinska Institute have crossed these bacteria with regular yogurt and are now trying to make a transgenic yogurt that will allow us not to brush our teeth.

The total weight of bacteria living in the human body is 2 kilograms.

There are about 40,000 bacteria in the human mouth. During a kiss, 278 different cultures of bacteria are transferred from one person to another. Luckily, 95 percent of them are harmless.

Conclusion

The role of prokaryotes in nature and human life is enormous. Bacteria, living in almost all environments, often determine the various processes occurring in nature. Bacteria were the first inhabitants of the Earth. The first bacteria arose on earth over 3 billion years ago.

Due to the action of bacteria, the appearance and chemical composition the shells of the Earth has changed, and thanks to this, the emergence of other forms of life (for example, plants) has become possible. Thanks to bacteria, the living shell of the Earth, the biosphere, began to develop. Bacteria that came to land before plants took part in soil formation and created the conditions for plants to land on land. At present, the role of bacteria is also very large.

1. Soil bacteria - decay bacteria. They recycle the dead organic matter. If it were not for these bacteria, then the surface of the earth would be covered with a thick layer of the remains of dead organisms. The cycle of substances in nature is provided by these bacteria. Decompose dead remains to mineral salts, which are absorbed by plants.

2. Nitrogen-fixing bacteria. They settle on the roots of leguminous crops (peas, alfalfa) and absorb nitrogen from the air, thereby enriching the soil with this element necessary for plant growth.

3. Lactic acid - used for making sour cream, kefir, fermented baked milk, cheese, sauerkraut, as well as for the production of silage.

4. E. coli - human companion. Lives in the intestines, helps break down milk sugar and produce vitamins.

5. Pathogenic bacteria - are the causative agents of many diseases such as: tuberculosis, plague, dysentery, tetanus.

6. While admiring the blue flames on your gas stove, remember the smallest workers who made natural gas for you. it methanobacteria , they process bottom residues, resulting in the formation of marsh gas - methane, which we use in everyday life.

7. Biotechnology, genetic engineering - a branch of modern biology, where bacteria are also indispensable. By inserting the necessary genes into the nuclear substance of bacteria, scientists force them to produce insulin, a drug used in the treatment of diabetes.

Conclusion

We pass a verdict - bacteria live, because. without it, many processes will stop, and the ecological balance will be disturbed.

Ah, this habitat! All are interconnected by exchange, food chains, composition, structure, fate ...

In the thickets, and in the ridges, and in the villages, Where life breathes and moves, May there always be balance! Be afraid to disturb it!

Bibliography.

A.G. Elenevsky, M. A. Biology. Plants, fungi, bacteria. Bustard, 2001

Biology grade 6. Lesson plans according to the textbook by I.N. Ponomaryora. Author-compiler G.V. Cherednikov. Volgograd. "Teacher" 2008 pp.144-146

Biology 10-11 class. Lesson plans for studies by V.I. Sivoglazov. Author-compiler T.V.Zarudnyaya. Volgograd. "Teacher" 2008 Pages 70-71

General biology. Grade 9. V.B. Zakharov, A.G. Mustafin, Moscow. Enlightenment 2003. p. 44 - 46.

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Application

Variety of bacteria