Dr. Dannelly’s BIO 274 – Flashcards
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| Pathogenic |
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| Disease-causing microbes |
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| Microbes in our lives |
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| Decompose organic waste Are producers in the ecosystem by photosynthesis Produce industrial chemicals such as ethanol and acetone Produce fermented foods such as vinegar, cheese, and bread Produce products used in manufacturing(cellulase) and disease treatment(insulin) |
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| Knowledge of microorganisms allow humans to... |
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| Prevent food spoilage Prevent disease occurrence Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories |
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| Linnaeus established what? |
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| The system of scientific nomenclature Each organism has two names: The genus and specific epithet(species name) |
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| Scientific names |
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| Are italicized or underlined -The genus is Capitalized; the species is lowercase Are "Latinized" and used worldwide After the first use, scientific names may be abbreviated with the first letter of the genus and the species |
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| E. coli |
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| Honors the discoverer, Theodor Escherich Describes the bacterium's habitat-the large intesine, or colon |
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| Staphylococcus aureus |
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| Describes the clusters(staphylo-) spherical(cocci)cells Describes the gold-colored(aureus)colonies |
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| Types of microorganisms |
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| Bacteria Archaea Fungi Protozoa Algae Viruses Multicellular animal parasites |
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| Bacteria |
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| Prokaryotes Peptidoglycan cell wall Binary fission For energy, use organic chemicals, inorganic chemicals, or photosynthesis |
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| Archaea |
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| Prokaryotic Lack peptidoglycan Live in extreme environments -Methanogens -Extreme halophiles -Extreme thermophiles These do not infect humans Live in the geysers and mud pots in Yellowstone, very hot and very acidic |
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| Fungi |
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| Eukaryotes(true nucleus, more advanced than prokaryotes) 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 unicellular Candid Albicani=yeast infection |
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| Protozoa |
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| Eukaryotes Absorb or ingest organic chemicals May be motile via pseudopods, cilia, or flagella |
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| Protozoa |
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| Eukaryotes Absorb or ingest organic chemicals May be motile via pseudopods, cilia(short,hair-like), or flagella |
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| Algae |
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| Eukaryotes Cellulose cell walls(plant like) Use photosynthesis for energy(plant like) Produce moleculare oxygen and organic compounds These release oxygen like a plant but they release probably more than a plant The red tide that happens in the ocean is caused by red algae and it produces toxins Algae does not produce diseases |
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| Viruses |
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| Acellular(don't have cells, not alive by themselves, can't replicate on their own, but they can inside us) Consist of DNA or RNA core(one or the other, never both) Coat may be enclosed in a lipid envelope(surrounded by lipid membranes) Are replicated only when they are in a living host cell Obligate parasite-enters one of our cells and uses it as a factory to replicate more virus cells |
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| Multicellular animal parasites |
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| Eukaryotes Multicellular animals(worms, lice, fleas) Parasitic flatworms and roundworms are called helminths Microscopic stages in life cycles |
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| Classification of microorganisms |
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| Three domains -Bacteria(prokaryote) -Archaea(prokaryote) -Eukarya --Protists --Fungi --Plants --Animals Eukaryotes are much closer related to Archaea than bacteria Dr. Whoes University of Illinois came up with this new way of classification |
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| When was the first microbes observed? |
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| 1673 Ancestors of bacteria were the first life on Earth(prokaryotes) |
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| The first observations |
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| 1665: Robert Hooke reported that living things are composed of little boxes or cells 1858: Rudolf Vichow said cells arise from prexisting cells |
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| Cell theory |
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| All living things are composed of cells and come from preexisting cells |
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| Anton van Leeuwenhoek |
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| 1673-1723 he described live microorganisms Created the first simple microscope |
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| Spontaneous generation |
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| The hypothesis that living organisms arise from nonliving matter, a "vital force" forms life |
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| Biogenesis |
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| The hypothesis that living organisms arise from preexisting life |
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| 1668: Francesco Redi |
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| Filled 6 jars with decaying meat -3 covered with fine net-->No maggots -3 open jars-->Maggots appeared This proved biogenesis |
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| 1745: John Needham |
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| Put boiled nutrient broth into covered flasks Nutrient broth heated, then placed in sealed flask-->Microbial growth |
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| 1765: Lazzaro Spallanzani |
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| Boiled nutrient solutions in flask Nutrient broth placed in flask, heated, then sealed-->No microbial growth |
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| 1861: Louis Pasteur |
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| Demonstrated that microorganisms are present in the air Nutrient broth placed in flask, heated, NOT sealed-->Microbial growth Nutrient broth placed in flask, heated, then sealed-->No microbial growth Pasteur's S-shaped flask kept microbes out, but let air in He disproved spontaneous generation, and proved biogenesis Aseptic technique came from this experiment He was the first "real" microbiologist |
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| The germ theory of disease |
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| 1860s: Applying Pasteur's work showing microbes are in the air, can spoil food, and cause animal diseases, Joseph Lister(Listerine) used a chemical disinfectant to prevent surgical wound infections 1876: Robert 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 |
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| Koch's Postulates |
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| 1.The same pathogen must be present in every case of the disease 2.The pathogen must be isolated from the diseased host and grown in pure culture 3.The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal 4.The pathogen must be isolated from the inoculated animal and must be shown to be the original organism |
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| 1796: Edward Jenner |
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| Inoculated a person with cowpox virus, who was then protected from smallpox Vaccination is derived from "vacca" for cow The protection is called "immunity" 30% of the people didn't survive if they got smallpox. The cowpox vaccine was so close to smallpox that it worked for both diseases. He took blood from an infected cow and injected it into humans...couldn't do that today |
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| The first synthetic drugs |
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| Quinine from tree bark was long used to treat malaria Paul Ehrlich speculated about a "magic bullet" that could destroy a pathogen without harming the host. 1910: Ehrlich developed a synthetic arsenic drug called Salvarsan to treat syphilis 1930's: Sulfonamides were synthesized(antimicrobial drug) If you were given too much salvarsan it would kill you |
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| 1928: Alexander Fleming |
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| Discovered the first antibiotic Fleming observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus 1940s: Penicillin was tested clinically and mass produced He accidently discovered it because it started to grow on his culture and he noticed that where it was growing, it killed or at least helped to shrink the S. aureus It was mass used in WW2 1942, it helped to save a lot of limbs due to its use. |
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| Terminology |
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| Bacteriology: study of bacteria Mycology: study of fungi Virology: study of viruses Parasitology: study of protozoa and the parasitic worms |
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| Simple microscope |
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| Has only one lens: basically a magnifying glass but slightly stronger |
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| Light microscopy |
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| The use of any kind of microscope that uses visible light to observe specimens Types of light microscopy: -Darkfield microscopy -Phase-contrast microscopy -Differential interference contrast microscopy -Flourescence microscopy -Confocal microscopy |
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| Compound light microcopy |
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| In a compound microscope, the image from the objective lens is magnified again by the ocular lens Total magnificatio=objective lens x ocular lens Resolution is the ability of the lenses to distinguish two points(objects) A microscope with a resolving power of 0.4nm can distinguish between two points>or=to 0.4nm apart Shorter wavelenghts of light provide greater resolution, the more light, the more resolution. The refractive index is a measure of the light-bending ability of a medium The light may bend in air so much that it misses the small high-magnification lens Immersion oil is used to keep the light from bending |
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| Electron microscopy |
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| Uses electrons instead of light The shorter the wavelength of electrons gives greater resolution |
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| Transmission electron microscopy(TEM) |
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| Ultrathin sections of specimens Light passes through specimens, then an electromagnetic lens, to a screen or film Light passes through specimen so you can see the internal structure |
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| Scanning electron microscopy(SEM) |
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| An electron gun produces a beam of electrons that scans the surface of a whole specimen Secondary electrons emitted from the specimen produce the image You only see the surface of the specimen |
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| Preparing smears for staining |
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| Staining: coloring the microbe with a dye that emphasized certain structures Smear: a thin film of a solution of microbes on a slide A smear is usually "fixed" to attach the microbes to the slide and to kill the microbes Live or unstained cells have little contrast with the surrounding medium. Researchers do make discoveries about cell behavior by observing live specimens Stains consist of a positive and negative ion A basic dye, the chromophore is a cation In an acidic dye, the chromophore is an anion Staining the background instead of the cell is called "negative staining" |
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| Simple stains |
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| Use a single basic dye A mordant may be used to hold the stain(precipitate the stain) or coat the specimen to enlarge it |
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| Differential stains |
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| Used to distinguish between bacteria Gram stain-->most important stain, named after a person (Hans Christian Gram) Acid-fast stain |
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| Gram stain "differential stain" |
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| Classifies bacteria into gram-positive or gram-negative G-p bacteria tend to be killed by penicillin and detergents G-n bacteria are more resistant to antibiotics Allows us to differentiate between the 2 classes of bacteria |
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| Gram stain: The process |
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| Primary stain=Crystal violet-->both are Purple Mordant=Iodine-->Both are still Purple Decolorization(important step)=Alcohol-acetone-->Gram-positive still Purple, Gram-negative is Colorless Counterstain=Safranin-->Gram-positive is still Purple, Gram-negative is Pink |
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| Acid-fast stain |
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| They cannot be stained with the Gram stain, they have too much waxy lipid in their walls Stain waxy cell wall is not decolorized by acid-alcohol Mycobacterium(tuberculosis) Nocardia Detergent would be the only way to get the stain in/out |
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| Acid-fast stain: The process |
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| Primary stain=Carbolfuchsin(have to use heat)-->A-F is Red, Non-A-F is Red Decolorizing agent=Acid-alcohol-->A-F is Red, Non-A-F is Colorless Counterstain=Methylene Blue-->A-F is Red, Non-A-F is Blue |
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| Negative staining for capsules |
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| Cells stained Negative stain Sometimes use India ink to stain background, cell bodies stain too. The white halo around cells are the capsule, they don't stain. |
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| Prokaryote |
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| Comes from the Greek words for "prenucleus" One circular chromosome, not in a membrane No histones No organelles Bacteria:peptidoglycan cell walls(unique to bacteria, made of protein and sugar) Archaea:pseudomurein cell walls(very similar to peptidoglycan) Binary fission |
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| Eukaryote |
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| Highly organized Comes from the Greek words for "true nucleus" Paired chromosomes, in nuclear membrane Histones(protein found in nucleus, DNA is wrapped around it, like a filing system or filing cabinet) Organelles Polysaccharide cell walls Mitotic spindle |
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| Basic shapes of bacteria |
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| Bacillus(rod-shaped)(Shape, and a Scientific name is both Bacillus, be careful to know the difference) Coccus(spherical) Spiral -Spirillum(corkscrew shaped, rigid cell) -Vibrio(shaped like a comma -Spirichete(flexible corkscrew) |
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| Arrangements of bacteria |
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| Pairs: Diplococci, diplobacilli Clusters: Staphylococci Chains: Streptococci, streptobacilli |
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| Glycocalyx |
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| Official name for capsules Outside cell wall Usually sticky Capsule:neatly organized(tight) Slime layer:unorganized and loose Extracellular polysaccharide allows cell to attach Capsules prevent phagocytosis(too slimy for it to occur) The bacteria can eat the polysaccharide if they are in a pinch for food You can see in the microscope a capsule because they are very thick, you can't see slime layer, it is too thin. Your teeth have biofilm on them |
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| Flagella |
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| Not all bacteria have flagella Outside cell wall Made of chains of flagellin(single protein that links together) Attached to a protein hook Anchored to the wall and membrane by the basal body Kind of like a string of pearls Usually about 10x longer than bacteria, rigid Basal body touches cytoplasm because cell tells it when to turn Basal body is the "motor"- it only can turn clockwise and counter clockwise-most bacteria only goes forward Gram-positive only has 1 basal body, Gram-negative has 2 |
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| Koch's postulate proved |
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| That microbes caused disease |
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| The ability of a microscope lens to distinguish two points is called what? |
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| Resolution |
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| Motile cells |
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| Rotate flagella to run or tumble Move towards or away from stimuli(taxis) Flagella proteins are H antigens(anything that causes immune system to get excited and produce antibiotics) Moving forward in straight line=run Bouncing around randomly=tumble Needs signal from cell for it to move towards food source or more concentrated part of food "McDonalds", or move away from toxic substances Chemotaxis=moving due to chemical Phototaxis=Photosynthesis, moving to get to the sun Response to a chemical Bacteria have glucose receptors on their head, smooth run until they don't have glucose. Then they stop and randomly tumble until they find glucose again. |
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| Fimbriae |
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| Hair-like projections that are all over the body of certain bacteria. Only found on Gram Negative bacteria. Extremely specific, on the end of the fimbriae they have receptors that bind to only the cells that they are looking for, most likely intestinal cells. |
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| Fimbriae |
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| Only found on Gram Negative bacteria. |
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| Pili |
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| Both Gram Positive and Negative have these. They look like fimbriae when they aren't active Facilitate transfer of DNA from one cell to another, this is called conjugation |
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| The cell wall |
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| Prevents osmotic lysis(busting due to being so saturated with pure water) Made of peptidoglycan(in bacteria only) |
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| Peptidoglycan |
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| Polymer of disaccharide(2 sugars) N-acetylgulcosamine(NAG) N-acetylmuramic acid(NAM) NAM is ONLY found in peptidoglycan If you remove cell wall the bacteria dies. So we aim our anitbiotics towards the cell wall. Penicillion works this way. They can't kill cell walls but they mess up the replication of new cells Peptidoglycan in Gram-Positive bacteria are linked by polypeptides |
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| Structure of Gram-Positive cells |
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| Chains of NAG and NAM that are linked together by peptide cross-bridges Rigid structure, like a lattus. Everything goes through this, not a filter at all Holds cell in shape Sheet of sugar protein lattus work that wraps around bacteria cell. Gram Positive has up to 40 layers, usually 20-40 layers Wall teichoic and lipoteichoic are only found in Gram-Positive cells Wall teichoic acids weave through the lattus to help strengthen the cell wall Lipoteichoic has a lipid part to it, hence the name, it sits in the membrane so it anchors the cell wall. |
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| Why does the Gram staining method work so well? |
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| Basically, the Gram-positive cells have so many peptidoglycan layers that the alcohol doesn't penitrate all of the layers making it stay purple. The Gram-negative only has 2-3 layers that get holes burnt into them taking out the color purple with it, then when the pink stain step happens it takes the stain while Gram-Positive stains don't |
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| Structure of a Gram-Negative cell |
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| Only have 2-3 cell wall(peptidoglycan)layers They have two plasma membranes that create a compartment making them more advanced and on their way to becoming eukaryote cells The compartment is in between the two plasma membranes Gram-negatives are more advanced than Gram-positive cells Porin protein lets positivley charged things in to the cell if they fit the size requirement Lipid A is extremely toxic to humans It is contained in the Gram negative cells If the cell dies, it will release the Lipid A and it will make you feel very sick, malays, fever, vomit. Sometimes when an antibiotic kills the cells it releases the Lipid A and makes you feel worse before it makes you feel better |
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| Gram-Positive cell walls |
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| Teichoic acids -Lipoteichoic acid links to plasma membrane -Wall teichoic acid links to peptidoglycan May regulate movement of cations Polysaccharides provide antigenic variation |
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| Gram-Negative outer membrane |
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| Lipopolysaccharides(first thing immune system sees), lipoproteins, phospholipids Forms the periplasm between the outer membrane and the plasma membrane Protection from phagocytes, complement, and antibiotics O polysaccharide antigen Lipid A is an endotoxin(called that because it is part of the cell) Porins(proteins)form channels through membrane(allows certain size and charged molecules into the cell |
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| The Gram stain mechanism |
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| Crystal violet-iodine crystals form in cell Gram-Positive(Purple) -Alcohol dehydrates peptidoglycan -CV-I crystals do not leave Gram-Negative(Red) -Alcohol dissolves outer membrane and leaves holes in peptidoglycan CV-I washes out |
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| Acid-fast cell walls |
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| Like Gram-Positive cell walls-they don't stain with Gram stains Waxy lipid(mycolic acid)bound to peptidoglycan(not a true wax, just have to melt or detergent to get stain in) Mycobacterium(TB) Nocardia |
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| The plasma membrane |
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| Phospholipid bilayer Peripheral proteins(outer edge of protein) Intergral proteins(go all through proteins) Transmembrane Proteins Wavy shape-indicates motion, fluid-like Fluid Mosaic Model Fat, oily Semi-permeable membrane-some things can, some things can't cross. Water crosses unaided, everything else has to be aided Cells don't like sodium-they like potassium(sodium potassium pump) |
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| Micelle |
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| When the phospho heads are all facing out in a circle with the fatty acid tails in the center. Hydrophobic fatty acid tales hide in the middle, hydrophilic heads interact with water. Think of the little balls of oil floating on top of the water. |
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| Fluid mosaic model |
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| Membrane is as viscous as olive oil Proteins move to function Phospholipids rotate and move laterally |
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| Chromatophores or thylakoids |
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| Photosynethetic pigments on folded membranes |
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| Damage to plasma membrane |
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| Damage to the membrane by alcohols, quaternary ammonium(detergents), and polymyxin antibiotics causes leakage of cell contents |
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| Simple diffusion |
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| Movement of a solute from an area of high concentration to an area of low concentration No ATP needed for energy Force driving this is osmotic pressure Where you have a high concentration of salt, water will follow If the concentration of salt inside the cell is the same as outside the cell, no movement will occur 0.85% is the amount of salt we have in our blood stream |
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| Hypotonic |
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| Low salt concentration |
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| Hypertonic |
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| high concentration of salt |
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| Facilitated diffusion |
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| Solute combines with a transporter protein and is moved across the membrane Sometimes it takes ATP, sometimes it doesn't |
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| Plasmolosis |
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| Process of killing bacteria by having too much salt present. Think of salt curing a ham(you can do the same with sugar). You add the salt to the ham, it draws the moisture out of the cells because they water goes where salt is, and it dehydrates and kills the bacteria |
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| Osmosis |
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| The movement of water across a selectively permeable membrane from an area of high water(or salt) to a low water(salt) concentration |
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| Osmotic pressure |
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| The pressure needed to stop the movement of water across the membrane |
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| Aquaporins |
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| Water channels(facilitated diffusion) |
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| Osmotic Lysis |
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| Cell wall breaking due to an influx of water in cell |
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| What happens in human cells under: |
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| High salt conditions? Cells shrink and die Low salt conditions? Cells swell and burst What is the isotonic concentration of salt for human cells? 0.85%(0.0085 grams salt per 100 ml of water) |
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| Active transport |
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| Requires a transporter protein and ATP |
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| Group translocation |
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| Requires a transporter protein and PEP(glycolitic, form of energy) |
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| Cytoplasm |
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| Everything inside the plasma membrane including the proteins and ribosomes; excluding the DNA |
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| Nucleoid |
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| Bacterial chromosome in its compressed structure in the cell |
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| The prokaryotic ribosome |
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| Ribosomes are the site of protein synthesis(in any cell, all cells have them) 70S total size 50s+30s subunits S is a measure of density or amount of space and weight that it takes up Eukaryote cells are 80S The difference between 70s and 80s is big enough that we can aim our antibiotics at the 70s and not even hurt/touch our 80s cells Made up of two units, one is 30s and the other is 50s but in this instance when we add them together we get a 70s because they basically fit together the way your hands would if you would make a fist with one hand and wrap your other hand around your fist...takes up less space that way Messenger RNA runs in between the two ribosomes |
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| Inclusions |
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| Metachromatic granules(volutin)=phoshate reserves Polysaccharide granules=energy reserves Lipid inclusions=energy reserves Sulfur granules=energy reserves Carboxysomes=ribulose 1,5-diphosphate carboxylase for CO2 fixation Gas vacuoles=protein covered cylinders(use gas bubbles to get the to sunlight) Magnetosomes=iron oxide(destroys H2O2)(Can tell if they are facing North or South, magnetic) |
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| Endospores |
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| Gram-Positive Resting cells-dormant state Resistant to desiccation(drying out), heat, chemicals Bacillus(genus of Anthrax) Clostridium(genus of botulism) Sporulation:endospore formation Germination:return to vegetative state They have found endospores in a mummies tomb that was ~30,000 years old that were still living, they are a well built cell Copy of genome(DNA) is in the middle of this cell It removes water from the cell because if it does not then when it is in the hot summer heat it will cause the water to produce steam that will then cause the DNA harm. Survival mechanism |
