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MicrobiologyAN INTRODUCTIONEIGHTH EDITIONTORTORA • FUNKE • CASEChapter 1, Part AThe Microbial World And You
Microbes and You•Microorganisms are organisms that are too small to be seen with the unaided eye.–Examples?•“Germ” refers to a rapidly growing cell.
•What do microbes do?•Decompose organic waste•Are producers in the ecosystem by photosynthesis•Produce industrial chemicals such as ethyl alcohol and acetone•Produce fermented foods such as vinegar, cheese, and bread•Cause disease•Mutualistic relationships - normal floraMicroorganisms:
•Produce products used in manufacturing (e.g., cellulase) and treatment (e.g., insulin)•A few are pathogenic, disease-causingMicroorganisms:
•Allows humans to–Prevent food spoilage–Prevent disease occurrence•Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories.Knowledge of microorganisms:
Naming and Classifying Microorganisms•Linnaeus established the system of scientific nomenclature.•Each organism has two names: the genus and specific epithet.•Part of a five kingdom system–Know the five kingdoms and characteristics•Three domain system–Know the domains and characteristics
•Are italicized or underlined. The genus is capitalized and the specific epithet is lower case.•Are “Latinized” and used worldwide.•May be descriptive or honor a scientist.Scientific names
•After the first use, scientific names may be abbreviated with the first letter of the genus and the specific epithet:•Staphylococcus aureusand Esherichia coliare found in the human body. S. aureusis on skin and E. coli, in the large intestine.Scientific names
•Prokaryotes•Peptidoglycan cell walls•Binary fission•For energy, use organic chemicals, inorganic chemicals, or photosynthesisBacteriaFigure 1.1a
•Prokaryotic•Lack peptidoglycan•Live in extreme environments•Include:–Methanogens–Extreme halophiles–Extreme thermophilesArchaea:Figure 4.5b
•Eukaryotes•Chitin cell walls•Use organic chemicals for energy•Molds and mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae•Yeasts are unicellularFungiFigure 1.1b
•Eukaryotes•Absorb or ingest organic chemicals•May be motile via pseudopods, cilia, or flagellaProtozoaFigure 1.1c
•Eukaryotes•Cellulose cell walls•Use photosynthesis for energy•Produce molecular oxygen and organic compoundsAlgaeFigure 1.1d
•Acellular•Consist of DNA or RNA core•Core is surrounded by a protein coat•Coat may be enclosed in a lipid envelope•Viruses are replicated only when they are in a living host cellVirusesFigure 1.1e
•Eukaryote•Multicellular animals•Parasitic flatworms and round worms are called helminths.