Microbiology Exam 1 Chapters 1 7 CHAPTER 1 I II Microbes in our lives microbes are minute things that individually are usually too small to be seen with the naked eye The majority are crucial for maintaining the balance of living organisms and chemicals in our environment A Examples i Marine and fresh water microorganisms are the basis of the food chain ii Microbes play an important role in photosynthesis iii Animals depend on microbes in their intestines for digestion and synthesis of nonessential vitamins B Commercial applications i Food industry vinegar fermentation of yeast and alcohol all utilize microbes ii Enzymes extracted from microbes can be manipulated to create different microbes cellulose digestive aids Naming and Classifying Genus 1st name always capitalized Species 2nd name not capitalized Types 1 Bacteria simple single celled organisms Their genetic material is not enclosed by a membrane making them prokaryotes pre nucleus They do however have a peptidoglycan cellular wall i ii iii Shapes include Bacillus rod spiral coccus spherical star shaped square Reproduction binary fission divide into two equal cells Nutrition organic chemicals derived from dead living organisms Some can manufacture their own food via photosynthesis iv Motion flagella 2 Archaea live in extreme environments They are prokaryotes but they lack the peptidoglycan cell wall component Don t usually cause disease i Methanogens produce methane as a waste product from respiration ii Extreme halophiles extremely salty environments like the Great Lake and Dead Sea Extreme thermophiles hot sulfurous water such as hot springs at Yellow Stone Park iii 3 Fungi eukaryotes meaning that they have distinct nucleus containing the cell s genetic material that is surrounded by a nuclear membrane Unicellular yeasts oval microorganisms that are slightly bigger than bacteria i ii Multicellular mushrooms can t carry out photosynthesis True fungi have chitin cell walls The most typical fungi are molds which form visible mycelia composed of long filaments that branch and intertwine ex fruit bread mold i Reproduction sexually and asexually ii Nutrition absorb solutions of organic material from the environment 4 Protozoa unicellular eukaryotes soil sea fresh water animal plant hosts i ii iii Locomotion pseudopods false feet flagella and cilia Amoebas have pseudopods Can live free or as parasites Reproduction asexually and sexually 5 Algae photosynthetic eukaryotes with a wide variety of shapes and reproductive forms asexual and sexual Usually they are unicellular with cell walls composed of cellulose They are abundant in fresh and salt water soil and are associated with plants They produce molecular oxygen and carbohydrates that are utilized by other organisms including animals Hence they provide an important balance for nature 6 Viruses extremely small acellular microorganisms that can only be seen with an electron microscope Their core can either be made of DNA or RNA surrounded by a protein coat called a capsid This protein coat can be encased by an additional envelope i Reproduction viruses rely on other cellular machinery of other organisms for reproduction Hence they are parasites 7 Helminthes flat worms and round worms Classification 1 Bacteria cell walls contain peptidoglycan 2 Archaea cell walls lack peptidoglycan 3 Eukarya a Protists slime molds protozoa and algae b Fungi unicellular yeasts multicellular molds and mushrooms c Plants mosses ferns conifers and flowering plants d Animals sponges worms insects and vertebrates III A brief history of Microbiology bacterial ancestors were the first living cells to appear on Earth A The First Observations after observing a thin slice of cork Robert Hooke reported that life s smallest structural units were cells developing the cell theory that all living things are composed of cells Anton van Leeuwenhoek made detailed drawings of what are now known to be bacteria and protozoa found in his feces teeth and rainwater B The Debate over Spontaneous Generation i Evidence Pro and Con Francesco Redi 1668 demonstrated a serious blow to the long held belief that large forms of life could arise from nonlife Needham 1745 vital force needed for spontaneous generation ii Theory of Biogenesis the claim that living cells only arise from preexisting living cells Pasteur 1861 reasoned that microbes in the air were responsible for contaminating nonliving matter such as broths in Needham s flasks He developed the s shaped flasks that allowed air to pass into the flasks but the curved neck trapped any airborne microorganisms that might contaminate the broth He also demonstrated that microbial life can be destroyed by heat and that methods can be devised to block the access of airborne microorganisms to nutrient environments forming the basis of aseptic techniques C The Golden Age of Microbiology after Pasteur s work there was an explosion of discoveries in microbiology 1857 1914 During this productive period microbiologists studied the chemical activities of microorganisms improved the techniques for performing microscopy and culturing organisms and developed vaccines and surgical techniques i Fermentation and Pasteurization Pasteur found that instead of air converting sugars to alcohol microorganisms called yeasts converted the sugars to alcohol in the absence of air fermentation In the presence of air bacteria change the alcohol in the beverage into vinegar spoiling the beverages The solution was to heat the beer and wine just enough to kill most of the bacteria that caused the spoilage a process coined pasteurization This is used today to reduce spoilage and kill potentially harmful bacteria in milk and some alcoholic drinks ii The Germ Theory of Disease the discovery of fermentation led scientists to the possibility that microorganisms might have similar relationships with plants and animals that microorganisms may cause disease 1865 Pasteur called to help fight silkworm disease In the 1860s Joseph Lister applied the germ theory to medicine by administering phenol solutions to surgical wounds due to his knowledge that phenol killed bacteria This was one of the first successful medical attempts to control infections caused by microorganisms 1876 Robert Koch discovered rod shaped bacteria Bacillus anthracis in the blood of cattle that died of anthrax He cultured the bacteria on nutrients and injected samples of the culture into healthy animals which died a Koch s postulates i
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