The number of described species of bacteria is about 15,000. The idea that they are all pathogens and always harmful to humans is not correct. Bacteria have remarkable beneficial properties.
Characteristics of Bacteria
1. Bacteria are tiny, simple, and microscopic in cellular organisms.
2. Bacteria are prokaryotic cells.
3. They are single-celled organisms.
4.They live alone or in groups.
5. Amitosis is the process of cell division.
6. The bacterial protoplasm is attached to the prokaryotic nucleus, meaning that the nucleus does not have a nuclear membrane, nucleolus, and chromatin mesh.
7. The protoplasm contains ribosomes and mesosomes.
8. Bacterial cells have a well-formed cell wall outside the cell membrane, the main component of which is mucopeptide.
9. Most bacteria are heterotrophic, some are autotrophic. The body of autotrophic bacteria contains photosynthetic pigments, such as bacteriochlorophyll, bacterioviridine.
10. Some of them are obligate anaerobes so they cannot survive in the presence of oxygen, while some facultative anaerobes can survive in the presence of oxygen.
11. They can withstand temperatures ranging from extreme cold (-17 degrees) to 60 degrees Celsius.
12. In bacteria, the lack of chromosomes prevents mitosis and meiosis cell division.
13. The main process of their reproduction is binary fission.
14. They are very sensitive to the phage virus.
15. Most of them accumulate energy by oxidizing inorganic salts.
16. Forms endospores to survive in hostile environments.
17. Bacteria can usually contain basic colors such as gram-positive or gram-negative.
18. Just ribosomes are present, with no cytoplasmic organelles such as plastids, mitochondria, or endoplasmic reticulum.
Example of bacteria: Escherichia coli, Lactobacillus, Streptococcus
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