MCB Exam 1 – Flashcards
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| Microbe |
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| Simple structures; Most abundant organism on Earth |
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| Prokaryotic cells |
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| Lack a membrane bound nucleus |
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| Eukaryotic cells |
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| Have more complex, membrane bound organelles |
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| Carl Woese |
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| Made 3 domain system in 1970's based on RNA: Eukarya, Bacteria, Archaea |
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| Domain Bacteria |
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| Usually single celled; cell wall of peptidoglycan; considered prokaryotes; some cause disease but most are beneficial and recycle elements |
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| Domain Archaea |
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| lack peptidoglycan in cell walls; many live in extreme environments; role in disease is unclear; some have unusual metabolic characterizations (ex. methanogens produce methane gas) |
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| Domain Eukarya |
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| Usually larger than Bacteria and Archaea; Ex. fungi, protozoan (grazers), animals, plants, slime molds, water molds (protists that grow in moist places), and algae |
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| Viruses |
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| Simple, most are just protein & nucleic acid; requires host to replicate; NOT PART OF 3 DOMAINS b/c it has no RNA |
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| Viroids and Virusoids |
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| Infections agents made of RNA |
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| Prions |
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| Infectious proteins (Causes diseases like mad cow disease) |
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| Definition of life |
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| -reproduction -energy use -have internal order -growth and development -maintain homeostasis -response to environmental changes |
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| Ribozymes |
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| Form peptide bonds and do cellular work; discovered by Thomas Cech in 1981 |
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| Earliest Metabolism used.. |
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| 1. inorganic materials for energy 2. photosynthesis (cyanobacteria release oxygen) |
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| How did cellular microbes evolve |
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| 1. Eukaryotes sexually reproduced 2. Archaea and Bacteria horizontally exchanged genetic info 3. Mutations led to new genes |
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| Leeuwenhoek |
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| Made lens out of glass; first person to accurately describe microorganisms; studied diarrhea and teeth scrapings |
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| Francisco Redi |
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| disproved spontaneous generation with meat covered with paper experiment |
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| John Needham |
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| Boiled then sealed mutton broth; didn't realize microorganisms could settle from air |
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| Lazzaro Spallanzani |
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| Sealed then boiled mutton broth; no microorganisms grew because they were killed in boiling (after Needham) |
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| Louis Pasteur |
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| SETTLED THE MATTER OF SPONTANEOUS GENERATION by using curved neck flasks; developed pasteurization; microorganisms ferment |
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| John Tyndall |
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| Proved dust carried microorganisms (after Pasteur) |
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| Ferdinand Cohn |
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| Heat resistant bacteria can produce endospores |
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| Bassi, Berkley, Bary |
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| Bassi- showed silkworm disease was from fungi, Berkeley- Potato famine was caused by water mold, fungi causes cereal crop disease |
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| Ignaz Semmelweis |
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| Realized high mortality rate at hospital was from people not washing hands after being in autopsy room |
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| Joseph Lister |
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| Figured out to clean instruments and wounds with phenol |
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| John Snow |
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| 1854 Cholera outbreak in London--500 died in 10 days, figured out it was from sewer leaking into water well |
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| Robert Koch |
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| Established relationship between bacillus anthracis and anthrax; developed Koch's postulates (links disease to microorganisms) |
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| Koch's postulates |
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| 1. microorganism must be present in sick person and absent in healthy person 2.Suspected organism must be isolated and grown as pure culture 3. Same disease must occur in healthy host 4. Organism must be isolated again from diseased host |
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| Edward Jenner |
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| Used vaccine procedure to protect from small pox (saved 8 year old boy); Before Pasteur!! |
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| Paul Ehrlich |
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| 1910: First chemotherapy; Salvation from syphilis |
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| Alexander Fleming |
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| 1928: Discovered first antibiotic-observed penicillin fungus killed S. aureus; 1940's: Penicillin is mass produced |
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| Basic vs. Applied Aspects |
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| Basic- individual groups of microbes, genetics, etc. Applied- practical problems like disease, water, food |
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| Resolution |
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| Ability to distinguish differences between things that are close together (Resolution of 0.2 microns means you can see between things that are 0.2 apart) |
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| Numerical Aperture |
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| Ability of lens to gather light (depends on refractive index of medium, increases as R.I. increases) |
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| Commonly used Flourochromes |
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| 1.Acridine orange and DAPI stain DNA 2. TRITC and FITC attach to antibodies that bind to cellular components (rabbit example to find disease) |
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| Heat Fixation |
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| Routinely used with bacteria and archaea; gives you overall morphology but inactivates enzymes/proteins |
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| Chemical Fixation |
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| Used with larger organisms; immobilizes proteins, lipids but protects delicate cell substructure (Ex. Formaldehyde) |
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| Simple staining |
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| Uses dyes to increase visibility and contrast (allows shape size arrangement to be seen); use chromophore groups (have double bonds) to bind cells and give color |
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| Basic dyes |
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| Positively charged bind to negatively charged molecules (proteins, nucleic acids) Ex. safranin, crystal violet |
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| Acid Dye |
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| Negatively charged so binds to positively charged structures and are repelled by cell surface; produces negative stain, good for seeing capsules. Ex. eosin |
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| Differential staining |
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| Divides microorganisms into groups based on properties; allows presence/absense of structures to be seen (flagella, endospores) |
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| Christian Gram |
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| 1884 he divides BACTERIA into two groups (Gram positive and Gram negative) |
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| Gram positive |
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| Thick wall of peptidoglycan; holds in purple color after staining |
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| Gram negative |
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| thin wall of peptidoglycan; only holds Safranin counterstain and is therefore pink |
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| Acid fast staining |
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| Uses heat and phenol to drive fuschion into cells that dont Gram stain (like Mycobacterium tuberculosis and M.leprae) because of their lipid cell wall |
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| Endospore staining |
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| Uses high heat and double staining to make green endospores on pink cells (Used on stain resistant micro's like Bacillus and Clostridium) |
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| Flagella staining |
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| Can only be seen in electron microscope; uses mordant and stain to increase size of flagella |
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| Why do electron microscopes have better resolution than light microscopes? |
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| Electrons have a shorter wavelength than light |
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| Electron cryotomography |
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| Created in 1990's to freeze native state of organism in vacuum and create 3d images by putting together many different angled pictures (used on cytoskeletal structures, flaggelar motors, etc) |
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| Macroelements |
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| Needed in large amounts 1. C,O,P,S,N,H - found in organic molecules like proteins, nucleic acids 2. Ca,Mg,K,Fe - exist as cations and responsible for enzyme activity and biosynthesis of ATP by electron transport |
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| Makeup of Important Cell Molecules (4) |
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| 1. Proteins- CHONS 2. Nucleic acids- CHONP 3. Lipids- CHOP 4. Carbohydrates- CHO |
