Ic02 - the Causes and Spread of Infections

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The Causes and Spread of Infections CANDIDATE NAME: DATE: IC02 Page 0 10/13/2013 IC02 - THE CAUSES AND SPREAD OF INFECTIONS MICRO-ORGANISMS ARE OFTEN DEFINED AS: Collin English Dictionary Definition: noun any organism, such as a bacterium, protozoan, or virus, of microscopic size WHAT ARE THE FOLLOWING AND GIVE AT LEAST ONE COMMON ILLNESS, DISEASE OR INFECTION THAT THEY CAN GIVE. BACTERIA Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most habitats on the planet. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in plants, animals, and have flourished in manned space vehicles. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. Once regarded as plants constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Some of the most deadly diseases and devastating epidemics in human history have been caused by bacteria.   Cholera Diphtheria   Dysentery Plague   Pneumonia Tuberculosis   Typhoid Typhus VIRUSES A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea. The average virus is about one one-hundredth the size of the average bacterium. Most viruses are too small to be seen directly with an optical microscope.     These disease-bearing organisms are known as vectors. Influenza viruses are spread by coughing and sneezing. Norovirus and rotavirus,

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