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Unformatted text preview: Chapter 27 and 28 The Hidden World of Microbes Microbes- living an nonliving things that are too small to be seen without a microscope (ex: viruses and bacteria) o Prokaryotes range in size from 0.2-1.0 micrometers in size o Unicellular eukaryotes range in size from 10-100 micrometers o How big is a micrometer?1/1,000,000 of a meter. (The period at the end of a sentence is about 1000 micrometers) o In general, eukaryotes are larger than prokaryotesbut not always Majority of bacteria do not cause disease in humans o Viruses are not considered living thingstherefore they can be found in none of the 3 domains of life!! o Viruses can infect any species found on earth o Viruses have one goalto reproduce Other biological entities- even smaller than bacteria. Not considered organisms because they dont have all the characteristics f living organisms 1. Viruses- small (.05-.2 um) and come in many different shapes. Vary in morphology o Have 2 main components: o Genome- genetic information. Can either be single-stranded or double- stranded DNA or RNA o Capsid- protein coat which surrounds and protects the genome. And surrounding the capsid is called the envelope (phospholipid bilayer) o Viruses hijack cells. Only way viruses can survive is in a host....
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