Bacteria - Reproduction And Development Of Bacteria, Growth Factors

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Bacteria - Reproduction And Development Of Bacteria, Growth Factors
Bacteria - Reproduction And Development Of Bacteria, Growth Factors

Video: Bacteria - Reproduction And Development Of Bacteria, Growth Factors

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Video: Microbiology - Bacteria Growth, Reproduction, Classification 2023, February

Last updated 30th January 2018 at 00:52

Reading time: 5 min

A living protozoan microorganism with a cellular structure is a bacterium. But, despite its simplicity, it is one of the most interesting to study. All bacteria are capable of reproduction by division.

It has always been interesting for scientists to observe how bacteria multiply. The micro section of biology - bacteriology - deals with the study and observation of bacteria.

Currently, approximately ten thousand species of bacteria have already been studied and described. But it is assumed that in fact their number is estimated at a million.

They surround us all our life, they can be found in water, earth, on our body and even in the atmosphere. The lifestyle of bacteria is unique in its own way. Their peculiarity is that, unlike fungi, bacteria do not have a clearly defined nucleus.

On microscopic examination, it can be noted that the bacterium has a different shape. Cocci, for example, have a rounded shape, chlamydiae have a spherical shape, and mycoplasma has the shape of a bulb or thread.

They, like all mankind, have a macromolecule called DNA (deoxyribonucleic acid). DNA in bacteria is responsible for storing and transmitting genetic information from one generation of microorganisms to the next. The metabolism of bacteria (metabolism) is almost the same as that of many living organisms.

The role of bacteria in the biosphere and our lives should not be underestimated. For example, soil fertility is achieved by active work and waste products of soil bacteria. In agriculture, fertilizers are created for these purposes.

They also play their role in human life. There are bacteria that can harm a person, such as E. coli. As well as useful lacto and bifido, which make up the human microflora.

Everyone knows words like probiotics and prebiotics.

Probiotics help our gastrointestinal tract to carry out its daily function - to digest food, build local immunity, and produce hormones such as serotonin.

There are microorganisms - pests for humans. Many bacteria are pathogenic and can cause disease and bacterial infections. For example, tuberculosis, diphtheria, whooping cough, diphtheria, tetanus, and cholera. There are a great many of them, and most of them, modern medicine has already learned to win.

Factors affecting the growth and development of bacteria:

  • Humidity level
  • Lighting
  • PH level
  • Environment composition
  • Temperature regime

Consider the most important of them, their effect on division and reproduction.


  • 1 Humidity
  • 2 Acidity and pH - balance
  • 3 Parasitic bacteria

    3.1 Similar articles


For growth and development, bacterial cells require a certain percentage of moisture levels. The bacteria need it in order to keep them alive. Almost all bacteria and living organisms love moisture.

In such conditions, they feel great. If the humidity level suddenly drops below 20%, this leads to destructive and stopping development consequences.

Acidity and pH - balance

Acidity plays an almost dominant role in influencing the development of bacteria. It is usually denoted by the pH sign and takes into account the range from zero to fourteen. Growth requires extreme values ​​from 4 to 9. At 9, almost all of the familiar microorganisms stop growing.

In the bulk, they stop growing already at 4 pH. The ideal habitat is neutral acidity.

  • Acidic environment - from 0 to 6 pH
  • Alkaline medium - 8 to 14 pH
  • Neutral medium - 7.07 pH.

Lactic acid bacteria (acidophilic) should be distinguished separately. They love an acidic environment and when they get into it, for example, in milk, they begin to work in a special way, processing carbohydrates into lactic acid. They are the most important manufacturers of products containing probiotics useful for human microflora.

The beneficial properties of acidophiles are also used in pharmaceuticals. Scientists have found positive properties and are using them in the production of medicines not only for the intestines, but also for many other organs. In the household, women often use the beneficial properties of bacteria.

Many every year make preparations and twists for the coming season without vegetables and fruits. By lowering acidity by adding vinegar, it makes an acidic environment. By this we achieve the death of pathogenic microorganisms.

In favorable conditions, bacteria divide, thereby increasing their population, every twenty minutes. With increased sunlight from exposure to rays, reproduction stops. Some bacteria even react to the planet's magnetic field.

Bacteria make up the normal human microflora, are found on the skin, mucous membranes and even inside a person, for example, in the intestines. Bacteria exist even in the air. We can say our whole world is bacterial in its own way.

Bacteria have different methods of reproduction, some do not have a sexual process and multiply by budding or by cross-division. Others have a sexual process, but in the most primitive form.

To have an idea of ​​the life cycle of this microorganism, you need to study the main eight phases of development:

First phase

"Latent" - the resting phase, lasting from the moment of settling in the plant environment until the beginning of the increase in the population (approximately 60 to 120 minutes). The rates are directly proportional to the environmental conditions.

Second phase

"Delayed reproduction" - the multiplication process takes place, cells multiply and divide rapidly, and increase in size at a high speed. Duration up to 120 minutes.

Third phase

"Logarithms" are the active reproduction phase. During this phase, the maximum possible development and division of bacteria is achieved. Division occurs in progression. From two - into four cells. From four to eight cells. From eight to sixteen, etc.

Fourth phase

"Negative acceleration" - the rate of reproduction decreases sharply, and the rate of death increases. The duration ranges from 100 to 120 minutes.

Fifth phase

"Stationary maximum" is a phase created so that cells can multiply. Reproduction picks up speed again, and covers the number of cells that died earlier.

Sixth phase

"Acceleration of death" - from the name of this phase, one can conclude that the number of dead bacteria is several times greater than the number of surviving cells, one might say a phase of poor existence.

Seventh phase

"Logarithmic death" - cells die off at the same rate, at the same time the division process first slows down and then stops altogether.

Eighth phase

“Decreasing rate of death” - if the nutrient medium allows bacteria to remain alive, then they stop dying and enter the resting phase. This is not an obligatory phase, which exists only if there are favorable conditions for the life process.

Parasitic bacteria

The well-known "salmonella" causes a serious infectious disease salmonellosis. It also develops under certain conditions. For development, it requires a temperature regime of 37 degrees Celsius. And even in a cooled state, they can be in the resting phase with the ability to divide up to 140 days and not die.

If a product contaminated with salmonella does not undergo the necessary heat treatment, human infection cannot be avoided. Infection with salmonellosis is accompanied by all the "unpleasant" symptoms of poisoning.

A publicly available product has every chance of becoming infected. You also need to be careful when preparing food. If you are not sure if the knife is on a clean table, it is best not to neglect repeated washing. The knife used to cut raw meat should be immediately sent to the sink to prevent accidental use for other products.

At home, it is impossible to find out in advance whether the meat is contaminated. The bacteria does not alter the product. The taste, color, appearance of the product remains the same. Most often, salmonella can be found in eggs, milk, and meat.

Over the years, many strains have mutated and become resistant to basic disinfectant solutions and outdated antibiotics. Salmonella are so tenacious that they can live and inhabit for about five months in open water, and on chicken eggs for almost the whole year.

This bacterial parasite poses the greatest danger to a fragile child's body, pregnant women and weakened individuals.

The disease in farm animals goes away without symptoms and the breeders are often unaware of the disease.

You can get infected with salmonellosis through at least two ways:

  1. Contact - household method - infection occurs from one sick person to another.
  2. Food method - contamination through dairy products, unwashed eggs or raw meat.

Understanding the structure of life, development, growth and reproduction of microorganisms, the question "what are bacteria for" disappears by itself. At the heart of all living things are bacteria. Any microorganism that lives on our body and in our home performs its function.

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