Bacteria: a way of a food, features of a structure, an inhabitancy

In this article, we will consider the most ancient organisms - bacteria. The diet and habitat of these organisms are very diverse. How are these characteristics interrelated?

General characteristics of bacteria

Bacteria are a group of unicellular microscopic organisms. They are prokaryotes. This means that their cells do not contain a formed nucleus. Their genetic material is represented by a circular DNA molecule located directly in the cytoplasm.

The forms of bacterial cells are very diverse. They can have the form of a ball, rods, bunches of grapes, spirals, sprouts, cube, etc. The surface apparatus of bacteria is represented by a permeable membrane, a mucous capsule and a cell wall consisting of murein or pectin. The cytoplasm of prokaryotes contains ribosomes and elements of the cytoskeleton.

Bacteria: diet and habitat

Due to the simplicity of the structure, the bacteria have mastered all habitats. They are found in water, soil, air, rocks, hot springs, on the surface of the body, in the internal organs of plants, animals and humans. By way of nutrition, bacteria are both auto- and heterotrophs.

The former contain chloroplasts in their cells, due to which photosynthesis is carried out. As a result, a glucose carbohydrate is formed, which is used to carry out various vital processes. Organisms that use solar energy for the synthesis of organic substances are also called phototrophs. These include green, purple and cyanobacteria.

Another group of autotrophic bacteria uses the energy of chemical bonds for vital activity. They convert complex compounds into simpler ones. This process is called chemosynthesis. Examples of such organisms are sulfur-, iron- and nitrogen-fixing bacteria.

A group of heterotrophic prokaryotes is also quite numerous. The source of their food depends on the environment. Depending on this, three groups of bacteria are distinguished:

• Saprotrophs;
• Parasites;
• Symbiotic organisms.

Let's consider each of them in more detail.

Saprotrophs

This group of bacteria lives in all environments that contain organic substances. It can be soil, plant and animal organisms. For example, rotting bacteria by diet are saprotrophs. They decompose the organic matter, extracting nutrients from it.

This is also the way to feed lactic acid bacteria. Their ability to ferment carbohydrates is widely used in the food industry. Kefir, fermented baked milk, cottage cheese, yoghurt - all these are the products of vital activity of prokaryotes of this species.

Parasites

Parasitic bacteria, whose diet is also heterotrophic, live inside or on the surface of other organisms. Feeding on the products of the hosts, they cause serious diseases. For example, a dysenteric rod that multiplies in the intestines, causes weakness, fever, headache, and upset of the stool are all manifestations of dysentery. "Disease of dirty hands" is often called salmonellosis, typhoid fever and cholera. All of them are caused by ingestion of parasitic prokaryotes into the body.

Dangerous diseases of humans and animals are tuberculosis, anthrax, tetanus, tonsillitis, diphtheria, glanders, brucellosis. The mechanisms of their entry into the body are different:

• The use of contaminated water or products;
• Airborne droplet path;
• Non-compliance with hygiene.

Symbiotic bacteria

Many organisms are able to enter into mutually beneficial relationships with representatives of other wildlife kingdoms. The bacteria are not an exception. The diet of the representatives of this group is also heterotrophic. However, they feed on ready-made substances of other organisms, without harming them. In addition, such cohabitation has many benefits.

An example of such a manifestation is nitrifying bacteria, which live in the roots of leguminous plants. Getting there from the soil through the cracks of the cover cloth, they begin to multiply actively. As a result, small but numerous bubbles form. This type of microorganism is able to fix nitrogen, which is part of the air, and convert it into a form that is accessible to plants. Thus from plants they receive nutrients which are in an aqueous solution.

The symbiotic bacteria of man are prokaryotes living in his intestines. Here they produce enzymes that further promote the cleavage of a number of organic compounds. Bacteria of the skin and mucous membranes prevent the dispersal of "alien" prokaryotes.

So, bacteria are unicellular prokaryotic organisms. They can both independently synthesize organic substances (autotrophs), and eat ready (heterotrophs).