What is Microorganisms Microorganisms are creatures that are not directly visible to the unaided eye, with dramatical biologic diversity. Viruses, bacteria, fungi, protozoa and some algae are all in this category All with the exception of plants and animals
named Genus name given first, followed by the species name Genus name given first, followed by the species name
virus The smallest in size Noncellular No typical cell structure no enzymes involved in energy metabolism Depend on living cells Contain either RNA or DNA
bacterium unicellular prokaryote Have nucleoid lack of karyotheca (nuclear membrane ) and nucleolus Contain DNA and RNA Single strand,circular naked DNA have cell wall Its organelles are incomplete
fungus Have true nuclus, have nuclear membrane and nucleolus Unicellular or multicelulla
Distribution of microorganisms Air Soil Water Animals Human body
Microorganisms and Human Beings Beneficial activities: Most microbes are of benefit to human beings, some are necessary ( nitrogen, carbon cycles, etc) Harmful activities: A portion of microbes cause diseases and are poisonous to human, and these are really that concern us in the study of medical microbiology, etc.
Microbiology Microbiology is the biology of microorganisms. It is a bioscience for the study of the evolution, Classification, morphology, physiology, genetics, ecology of microbes under certain definite conditions, The law of their life activities, and their interaction with human being, animals or plants as well as with natural environment.
The Importance of Microbiology Environment Medicine Food Industry Biotechnology Research
History of Microbiology Experience phase 经验时期 Experimental phase 实验时期 Modern phase 现代微生物学时期
Koch’s postulates The microbe must be found in the body in all cases of the disease It must be isolated from a case and grown in a series of pure culture in vitro It reproduce the disease on the inoculation of a late pure culture into a susceptible animal The microbe must be isolated again into pure culture from such experimentally caused infection.