Isabella Bedoya MCB2004 Exam 1 Study Guide Lesson 1 Summary 6 major groups studied by microbiologists Prokaryotes o Bacteria Prokaryotes Peptidoglycan made up of carbohydrate polymers cross linked by peptides cell walls Binary fission For energy use organic chemicals inorganic chemicals or photosynthesis Lacks a real nucleus o Archaea Prokaryotes Lacks peptidoglycan in their cell walls Commonly live in extreme environments Include Methanogens Extreme halophiles high concentration of salt Extreme thermophiles Eukaryotes Cellulose cell walls Use photosynthesis for energy Produce molecular oxygen and organic compounds Eukaryotes o Algae o Protozoa Eukaryotes Absorb or ingest organic chemicals May be motile via pseudopods cilia or flagella o Fungi Eukaryotes Chitin cell walls Use organic chemicals for energy Yeasts are unicellular Molds and mushrooms are multicellular Viruses o Acellular o DNA or RNA genome o Genome is surrounded by a protein coat called capsid o Coat may be enclosed in a lipid envelope Isabella Bedoya parasites Microbes o Viruses are replicated only when they are in a living host cell intracellular Microbes are living creatures except for viruses o Have proteins nucleic acids lipids sugars same as us chemically o Metabolize grow reproduce and respond to environment Microbial genomes many are sequenced o Allow them to adapt to different environ o Genome organism s total genetic content o Complete genome sequence known for many species The phage X174 5368 bps was sequenced by Fred Sanger in 1977 The complete genome sequence of a cellular microbe is Haemophilus influenza 2 million bps 1 700 genes in 1995 Over thousands bacteria archaea Tens of thousands of viruses First draft of human genome was published in 2000 Microbes have greatest diversity of genomes o Important for understanding evolutions Microorganisms o Produce fermented foods such as vinegar cheese and bread o Produce industrial chemicals such as ethanol and acetone o Produce medicine e g insulin interferon vaccine and products used in manufacturing e g cellulase o Widely used as tools in biomedical research o Decompose organic waste o Are producers in the ecosystem by photosynthesis o A few are pathogenic disease causing o Knowledge of Microbiology o Allows humans to control growth of microbes o Microorganisms are so small and cannot be seen by unaided eyes o Microorganisms are very diverse 1 is culturable and studied o Microorganisms are helpful but sometimes are harmful Lesson 2 Objectives List the three domains of cellular organisms 1 Prokaryotes 2 Eukaryotes 3 Viruses Compare spontaneous generation and biogenesis Isabella Bedoya hypothesis Francesco Redi 1668 o Spontaneous generation living organisms arise from nonliving matter o Biogenesis living organisms arise from preexisting life alternative Redi took six jars which he divided in two groups of three In one experiment in the first jar of each group he put an unknown object in the second a dead fish in the last a raw chunk of veal Redi took the first group of three and covered the tops with fine gauze so that only air could get into it He left the other group of jars open After several days he saw maggots appear on the objects in the open jars on which flies had been able to land but not in the gauze covered jars In the second experiment meat was kept in three jars One of the jars was uncovered and two of the jars were covered one with cork and the other one with gauze Flies could only enter the jar with the lid off of it and in this maggots appeared In the jar that were covered with gauze maggots stayed on the gauze and did not live John Needham 1745 John Needham was a proponent of spontaneous generation and his beliefs were confirmed when after boiling beef broth to kill all microbes within the span of a few days cloudiness of the broth indicated the re spawning of microscopic life He was trying to prove spontaneous generation but his experiment was flawed Lazzaro Spallanzani 1765 Lazzaro Spallazani noted a flaw in Needham s experiment The containers holding Needham s beef broths had not been sealed upon boiling So Spallazani modified Needham s experiment boiling infusions but immediately upon boiling he melted the necks of his glass containers so that they were not open to the atmosphere The microbes were killed and did not reappear unless he broke the seal and again exposed the infusion to air Louis Pasteur 1800s Pasteur created unique glass flasks with unusual long thin necks that pointed downward These swan necked flasks allowed air into the container but did not allow particles from the air to drift down into the body of the flask Identify the contributions to microbiology made by Hooke and van Leeuwenhoek Pasteur Koch Jenner and Fleming Golden Age of Microbiology 1800s nineteenth century Hooke reported that living things were composed of little boxes or cells 1665 Isabella Bedoya Van Leeuwenhoek described live microorganisms that he observed in teeth scrapings rain water and peppercorn infusions 1673 1723 Pasteur showed that microbes are responsible for fermentation o Microbial growth is also responsible for spoilage of food demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to destroy the flavor of wine milk etc o Microbes are responsible for fermentation Fermentation is responsible for the conversion of sugar to alcohol to make beer and wine o Pasteurization is the application of high heat for a short time o Pasteur made vaccine for rabies and other diseases o Pasteur disapproved spontaneous generation Koch proved that a bacterium causes anthrax and provided the experimental steps Koch s postulates to prove that a specific microbe causes a specific disease 1876 Fleming discovered the first antibiotic o He observed that Penicillium fungus made an antibiotic penicillin that killed bacteria Staphylococcus aureus o 1940s Penicillin was tested clinically and mass produced Jenner first vaccine 1798 Understand Koch s postulates Koch s postulates are four criteria designed to establish a relationship between a causative microbe and a disease 1 Detect agent in host s with the disease 2 3 4 Re isolate the agent Isolate pure culture agent Induce disease in new host Explain the importance of recombinant DNA technology aka genetic engineering Recombinant DNA is DNA made from 2 different sources o Paul Berg 1960s inserted animal DNA into bacterial DNA and the bacteria produced animal protein Recombinant DNA
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