Microorganisms、too embarrassed to ask others about！（Part 3）

3. what are bacteria?
You're probably familiar with the word "bacteria," but if someone asked you about it, would you be able to explain it clearly? All living organisms, from microorganisms such as bacteria to humans, have cells as their basic unit. And there are two main types of cells. Prokaryotic cells, which have no cell nucleus, and eukaryotic cells, which have a cell nucleus, mitochondria, and other intracellular structures.
Bacteria represent the more primitive prokaryotic cells. Animals, plants, and fungi, on the other hand, consist of eukaryotic cells and are considered more advanced organisms. Bacterial cells are surrounded by a tough cell wall, just like an eggshell, with an inner cell membrane. Bacteria are "unicellular organisms," meaning that each individual cell is composed of a single cell, and they multiply by division; each cell is about 1/1000 mm in size, so individual cells cannot be seen with the naked eye.

Bacteria are morphologically divided into three categories: cocci, bacilli, and racemose bacteria. Cocci are ball-like, spherical bacteria. Bacillus rods are long bacteria and can range from rugby ball-like to rod-shaped. Lachen bacteria, as the name implies, are bacteria that appear twisted. Some bacteria also produce structures called spores when the surrounding environment deteriorates. Bacteria cannot multiply in the spore state, but spores are highly durable cells that are extremely resistant to high temperatures, drugs, and desiccation. When the surrounding environment is suitable for growth, the spores germinate into a viable form called a trophoblast and begin to multiply. Bacillus and Clostridium are well-known spore-producing bacteria.