how is bacteria useful for us prove with an experiment
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Answer:
Bacteria Overview
Bacteria are one-celled, or unicellular, microorganisms. They are different from plant and animal cells because they don’t have a distinct, membrane-enclosed nucleus containing genetic material. Instead, their DNA floats in a tangle inside the cell. Are viruses protists?
Individual bacteria can only be seen with a microscope, but they reproduce so rapidly that they often form colonies that we can see. Bacteria reproduce when one cell splits into two cells through a process called binary fission. Fission occurs rapidly in as little as 20 minutes. Under perfect conditions, a single bacterium could grow into over one billion bacteria in only 10 hours! (It’s a good thing natural conditions are rarely perfect, or the earth would be buried in bacteria!)
EXPERIEMENT
Experiment #1: Cheek Cell Swab
Make a culture dish using the instructions above. Once the culture dish is prepared, use a sterile cotton swab or inoculating needle and swab the inside of your cheek. Very gently rub the swab over the agar in a few zigzag strokes and replace the lid on the dish. You’ll need to let the dish sit in a warm area for 3-7 days before bacteria growth appears. Record the growth each day with a drawing and a written description. The individual bacteria are too tiny to see without a high-power microscope, but you can see bacteria colonies. Distinguish between different types of bacteria by the color and shape of the colonies.
Placing sensitivity squares in a petri dish
Experiment #2: Testing Antibacterial Agents
Preparing Sensitivity Squares
One method for testing the antibacterial effectiveness of a substance is to use ‘sensitivity squares.’ Cut small squares of blotter paper (or other absorbent paper) and then soak them in whatever substance you want to test: iodine, ethyl alcohol, antibacterial soap, antiseptics, garlic, etc. Use clean tweezers to handle the squares so you don’t contaminate them. Label them with permanent ink, soak them in the chosen substance, and blot the excess liquid with a paper towel.
Collecting Bacteria
Inoculating a bacteria cultureDecide on a source for collecting bacteria. For using sensitivity squares, make sure there is just one source, and keep each dish as consistent as possible. Sources could include a kitchen sink, bathroom counter, cell phone, or another surface you would like to test. Rub a sterile swab across the chosen surface, and then lightly rub it across the prepared agar dish in a zigzag pattern. Rotate the dish and repeat.
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