Bacteria Basics - They are Alive!Bacteria are the simplest of creatures that are considered alive. Bacteria are everywhere. They are in the bread you eat, the soil that plants grow in, and even inside of you. They are very simple cells that fall under the heading prokaryotic. That word means they do not have an organized nucleus. Bacteria are small single cells whose whole purpose in life is to replicate.
Okay. So we've told you they don't have an organized nucleus. True. They do have DNA. It is grouped in an area called the nucleoid. They have cell membranes like other cells and even a protective cell wall. Mind you, their cell wall is not like the one in a plant. It's a special kind that bacteria have for protection. They don't have any organelles, just ribosomes. (These are all characteristics of prokaryotes if you remember.)
What Do Bacteria Look Like?Very small. Very, very small. You might have seen pictures of some bacteria. Since we don't know what you have seen, we'll tell you there are three basic shapes. Spherical bacteria are in the shape of little spheres or balls. They usually form chains of cells like a row of circles. Rod shaped bacteria are look like the E. coli living in your intestine. You can imagine a bunch of bacteria that look like hot dogs. They can make chains like a set of linked sausages. Spiral shaped bacteria twist a little. Think about balloon animals for these shapes. It's like a balloon animal in the shape of a corkscrew.
What Do Bacteria Do?All sorts of things. Sorry to be so vague, but they do just about everything. Some help plants absorb nitrogen (N) from the soil. Some cause diseases like botulism. Some bacteria even live inside the stomachs of cows to help them break down cellulose. Cows on their own can digest grass and plants about as well as we do. They don't get many nutrients out of the plants and can't break down the cellulose. With those super bacteria, the cellulose can be broken down into sugars and then release all of the energy they need. Imagine if scientists could develop bacteria to live inside of us that would break down plants. That would be something. We could eat grass and leaves all day long.
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- Protozoa I
- Protozoa II
- Good Microbes
- Bad Microbes
- Humans and Microbes
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Bacteria: Energy Producers of the Future (US-NSF Video)
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