Bacteria
are the most plentiful living organism on the Earth.They
are the most smallest organism ,each consisting of a simple
, single cell.A few types of bacteria ,called germs ,cause
diseases in humans .But most bacteria are harmless, some
are very useful.They used in making drugs and foods.
Bacteria reproduce by binary fission(splitting in two). Reproduction by division means that bacteria can multiply very quickly,if the conditions are just right.Bacteria comes in three shapes-
Bacteria reproduce by binary fission(splitting in two). Reproduction by division means that bacteria can multiply very quickly,if the conditions are just right.Bacteria comes in three shapes-
- Cocci,called coccus are sp herical
- Bacilli, called a bacillus are rod shaped.
- Spirilla,one is called a spirillum are spiral
- shaped.
- First bacteria appear more than 900 millions years after Earth formed.Dutch scientist Antoni van Leeuwenhoek was the first person to see bacteria , in scrapping of his teeth in 1683.French scientist Louis Pasteur shows that some bacteria cause disease. in 1860's
- Now a days scientists research genetically modified bacteria to produce useful substances including anti-cancer vaccines.
- In 1928 ,British scientist Alexander Flemming was studying harmful bacteria by growing them in a glass dishes.Returning from a holiday ,he noticed that some dishes were infected with a blue penicillin fungus.This fungus released a chemical that killed harmful bacteria.This discovery lead to the development of penicillin,the first bacteria killing drug or antibiotic.
- Five diseases that bacteria causes .in humans.
- Acne-pimples can be sore and erupt.
- Dental caries-tooth decay that form cavities.
- Cholera-The major and most deadly symptom is severe diarrhea.
- Diphtheria- A ,rare respiratory illness .
- Tetanus -Serious disease causing muscles spasms.
- But bacteria are not always harmful.Some bacteria are very useful.-They are used to make yogurt and cheese.
- Bacteria
- Chemicals made by bacteria are used in the process of baking
- Some bacteria produce antibiotics that are used to kill other harmful bacteria
- Soil bacteria break down dead organism so their components can be recycled
- Some bacteria releases life giving oxygen in the air.
- INTERESTING FACTS-
- Light producing bacteria live inside the Hawaiian squid .At night , the bacteria mimic moonlight shining through the water, making the squid invisible to nearby , hungry predators.
- Ther are 1,000 trillion on an inside the human body.
- The number of bacteria in 1 gm of soil is 2.5 billion .
- The average length of a bacterium is 0.0001 cm.
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