Bacteria Essay Research Paper BacteriaBacteria are one

Bacteria Essay, Research Paper

Bacteria

Bacteria are one celled organisms that are found almost everywhere. Bacteria live in soil, air, water and food. They also live in and on plants and animals. Bacteria can be found on our bodies in places such as our noses, mouths and intestines. Most bacteria measure from 0.3 to 2.0 microns in diameter. This means that bacteria can only be seen through a powerful microscope. Bacteriology is the study of bacteria. Some kinds of bacteria are helpful. Other kinds of bacteria can cause serious disease. Bacteriologist study harmful bacteria to determine how they cause disease so that vaccines can be developed.

Certain kinds of bacteria are helpful to humans. Bacteria help in digestion in both humans and certain animals such as cattle and horses. Bacteria help break down food and also furnishes vitamins. Bacteria are important in certain kinds of foods such as vinegar and certain types of cheese and in sauerkraut. Bacteria can also help to decompose dead organisms and animal wastes into chemical elements.

Certain kinds of bacteria are harmful to humans, animals and plants. Some kinds of bacteria can cause diseases in human beings. These diseases include tuberculosis, typhoid fever, meningitis, leprosy, cholera and certain types of

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pneumonia. Bacteria can also cause diseases in animals such as anthrax. Plant

diseases caused by bacteria are fire blight ( in pear and apple trees) Citrus canker, tomato and potato wilt. These crop diseases can result in tremendous financial

losses for farmers worldwide.

Bacteria reproduction is largely asexual. Most bacteria reproduction is by fission which is a process of cell division in which one bacterium splits into two new ones. Fission may occur every 15 to 20 minutes under particularly favorable conditions of temperature, moisture and food supply. Within an estimated 24 hours, a cholera bacterium could produce an enormous number of offspring weighing more than 2,000 metric tons. This is only theoretically possible because there would not be nearly enough space and food for this large number of offspring. There are many parts of a bacteria cell. Nearly all bacteria have a protective layer called the cell wall. The cell wall also gives the cell it s shape and enables it to live in a wide range of environments. Another part of the cell is the capsule. The capsule is a slimy layer outside the cell wall. The capsule protects the cell by making the cell resistant to chemicals that can hurt it. All bacteria have a cell

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membrane, an elastic, bag like structure just inside the cell wall. Small molecules

of food enter the cell through pores in the membrane. Inside the membrane is cytoplasm, a soft jelly like substance. The cytoplasm contains many chemicals

called enzymes, which help build cell parts and break down food. Like all living things, bacteria cells contain DNA (deoxyribonucleic acid) which controls the

cells growth, reproduction and all other activities. The DNA can be found in the nucleus body in all organisms except blue- green algae. DNA is also in the nucleus, a part of the cell separated from the cytoplasm by a membrane.

There are four types of bacteria cells. Scientist usually divide bacteria into four groups according to the shape of the bacteria. Round bacteria are called cocci. Rod shaped bacteria are called bacilli. The type of bacteria that looks like bent rods are called vibrios. Spirilla is the type of bacteria that is shaped like a spiral. Two are more bacteria can link together and these combinations are described by using different prefixes. Some of the prefixes are: diplo (pair), staphylo (cluster) and

strepto (chain). An example of linked bacteria is streptococci which is round bacteria that are linked together.

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Most bacterial diseases can be prevented by vaccines. Vaccines are made in different ways depending on what kind of bacteria causes the disease. There are three main types of vaccines. One type is made from live bacteria. The second type is made from killed bacteria. The third type of vaccine is made from inactivated poisons produced by the bacteria. Certain pathogenic bacteria become harmless after they have been grown for a while in the laboratory. When these harmless living bacteria are injected into animals the animals become immune to the disease caused by the strain of bacteria. In the United States, most vaccines that are used to prevent tuberculosis contain living but harmless bacteria. Killed bacteria of certain strains can be used for vaccines. Most Americans are vaccinated against whopping cough with bacteria that has been killed with heat or chemicals. Certain bacteria cause serious diseases because they produce powerful toxins. Vaccines to prevent some of these diseases can be prepared by growing the bacteria in the Laboratory, isolating the toxins they produce, and inactivating the toxins with heat or chemicals. Most Americans are vaccinated against diphtheria and tetanus with vaccines made of inactivated toxins. Some bacteria can be controlled in ways other

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than vaccinations. Modern methods of treating sewage, preserving food, and purifying water have reduced the spread of certain bacterial diseases.

Bacteria has an interesting history. Simple forms of

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