What are the characteristics of bacteria?

1, bacteria are mainly composed of cell membrane, cytoplasm and nucleosome, and some bacteria also have special structures such as capsule, flagella and fimbriae. The nucleus did not form.

2. The individual of bacteria is very small. At present, the smallest known bacteria are only 0.2 microns long, so most of them can only be seen under a microscope. Most bacteria are between 0.5 and 5 μ m in diameter.

3. Bacteria are generally single-celled, with simple cell structure and lack of nuclei, cytoskeletons and membranous organelles, such as mitochondria and chloroplasts. According to these characteristics, bacteria belong to prokaryotes.

4. Bacteria are widely distributed in soil and water, or born with other organisms. The human body also carries quite a lot of bacteria. It is estimated that the total number of bacterial cells in human body and epidermis is about ten times that of human body. In addition, some species are distributed in extreme environments, such as hot springs and even radioactive waste, and they are classified as extreme microorganisms.

5. Bacteria have two nutrition modes: autotrophic and heterotrophic, among which heterotrophic saprophytic bacteria are important decomposers in the ecosystem, which makes the carbon cycle go smoothly. Some bacteria will carry out nitrogen fixation to transform nitrogen into a form that can be used by organisms.