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Microbiology Quiz 1 PowerPoint s 1 3 5 SCIENTISTS Anthony van Leeuwenhoek o 1st to discover microbes o Invented single lens magnifier Francesco Redi o Disproved spontaneous generation with cheesecloth Louis Pasteur o Father of modern microbiology o Saved French beer wine industry Fermentation was caused by living yeast which did not require oxygen for growth When the grapes or grain is contaminated with bacteria instead of yeast acetic acid is produced instead of alcohol o Helped further disprove spontaneous generation Air is filled with microorganisms Swan neck flasks o Developed first vaccines with attenuated strains Robert Koch o Realized that some diseases are linked to certain microbes o Made Koch s Postulates Edward Jenner Alexander Fleming o Deliberately infected patients with cowpox lesions o Discovered Penicillium mold made a substance that kills bacteria Howard Florey and Ernst Chain o Purified penicillin Carl Woese o Discovered archaea o Looked at 16S rRNA sequences FACTS Most microbes are 0 2 5 m Microorganism contradictions o Supersize microbial cells o Multicellular communities biofilms o Viruses Spontaneous generation matter through some kind of vital force Endospores Microbes are named using a binomial system heat resistant bacteria found in soil o Except for viruses idea that living organisms can arise from non living Koch s Postulates causative agent for a microbial disease set of guidelines for deciding which microorganism is the o 1 The microbe is found in all cases of the disease but is absent from healthy o 2 The microbe is isolated from the diseased host and grown in pure culture o 3 When the microbe is introduced into a healthy susceptible host the same individuals disease occurs o 4 The same strain of microbe is obtained from the newly diseased host Pure culture cell that divides into a population of genetically identical descendants clone culture where all of the cells descend from a given ancestral How to run an agar slowly diluting the sample by dragging the sterile loop across stimulation of an immune response by deliberate inoculation with the previous streak in order to spread out the microbes and allow them to separately colonize Immunization an attenuated pathogen or fragment of the pathogen eukaryotic ribosomes unharmed first commercial antibiotic to save human lives Penicillin Selective toxicity antimicrobials target prokaryotic ribosomes while leaving the the minimum distance to allow you to see two different objects Microbes are vital in the nitrogen cycle Resolution Biofilm community of microbes o More resistant than free cells Simple stains medium or surrounding tissue o Most common is methylene blue add intense color specifically to cells but not to the external Differential stains colorize one type of cell but not another o Example Gram stain Gram positive cells have thick cell walls which helps Prokaryotes them retain the crystal violet Bacteria Archaea o Prokaryotic cells don t have membrane bound organelles Eukaryotes Most prokaryotes share Eukarya o Thick complex outer envelope because many are in extreme environments and are constantly interacting with their environment allows them to adapt quickly to the environment o Compact genome in comparison to more complex organisms advantageous when it comes to gene replication o Tightly coordinated cell functions because they have to respond to their environment for rapid cell division separate the cell parts Fractionate Lyse cells by o Mild detergent o Sonication o Enzymes o Mechanical disruption Examples bead beater or high pressure of a French press X ray crystallography requires purified rigid structure NMR nuclear magnetic resonance can show areas of movement in a protein o Small proteins only Simple diffusion lets gas molecules O2 CO2 N2 small and uncharged small hydrophobic molecules and water molecules through the membrane cell wall cell membrane Cell envelope Weak acids and bases exist partially in uncharged form that can diffuse across the membrane and change the pH of the cell Passive transport Active transport molecules move along their concentration gradient molecules move against their concentration gradient o Requires energy from a reaction or ion gradient Phospholipids vary in o Phosphoryl head groups o Fatty acid side chains Hopanoids strengthen bacterial membranes Extremophiles Ester ether in archaea All archaea have ether links and methylation but not all have a monolayer and the subset of Archaea that live in extreme environments rings that s for extremophiles Peptidoglycan 1 molecule that acts as a cell wall o Counteracts osmotic pressure to prevent lysis o Determines cell shape o Made of glycan chains of 2 alternating sugars NAM NAG TYPES OF MICROBIAL SHAPES Coccus cocci spherical Bacillus bacilli rod shaped Coccobacillus coccobacilli short round rods Vibrio s curved rods Spirillum spirilli spirals Spirochete s helices Pleomorphic vary in shape Division along a single plane o Diplococci pairs o Streptcocci chains Division along 2 or 3 perpendicular planes o Cubical packets o Clusters Types of Microscopy 1 Transmission Electron Microscopy 2 Scanning Electron Microscopy 3 Light microscopy a Dark field is one type 4 Cryo electron microscopy 5 Immunofluorescence microscopy 1 3 4 2 3a 5

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NU BIOL 2321 - Microbiology Quiz 1

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