OCTC-Micro-Test 1 – Flashcards
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| Which disease was the 1st proven to be bacterial in origin? |
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| anthrax |
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| Who discovered penicillin? |
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| Flemming |
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| negative taxis (flagella movement) |
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| Movement away from |
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| positive taxis (flagella movement) |
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| Movement towards |
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| positive phototaxis |
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| Movement toward light |
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| positive chemotaxis |
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| Movement toward chemical |
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| negative chemotaxis |
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| Movement away from chemical |
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| negative phototaxis |
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| Movement away from light |
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| What causes negative chemotaxis, or negative phototaxis? |
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| Tumbles |
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| What causes the flagellum to swim forward and thus promotes positive chemotaxis or phototaxis? |
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| Runs |
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| What are biofilms |
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| Biofilms are a complex community of microbes that form a protective adhesive matrix that attaches microbes to surfaces |
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| How are biofilms made? |
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| Capsules allow the bacteria to attach to solid surfaces and form biofilms.and Fimbriae are found forming biofilms so both the glycocalyx and fimbriae form the biofilm. |
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| Where do biofilms form? |
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| Teeth Tonsils Infected tissues Plastic catheters IUD Metal pacemakers Industrial pipelines. |
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| Flagella |
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| located on Eukaryotic cells and protozoa.extensions of cell membrane; protozoa, sperm cells of mammals (also in bacteria) |
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| Cilia |
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| located ONLY on eukaryotic cells Bacteria do not have cilia!! |
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| Bacterial flagella can move by means of rotating flagella how many degrees? |
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| 360?. |
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| bacterial flagella are easily seen with which microscope? |
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| electron microscope. |
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| Bacterial Flagella are composed of which three parts? |
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| filament hook basal body |
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| what is bacterial flagella composed of? |
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| flagellin |
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| What is a sex pilus? (also called conjugations pilus) |
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| long hollow tubules composed of protein called pilin. |
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| What do sex or conjugation pilus do? |
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| Mediate the transfer of DNA from one cell to the other via a process termed conjugation. (a form a genetic exchange) Remember that bacteria produce asexually. |
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| Components of a bacterial cell wall |
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| Composed of peptidoglycan(PG), a complex polysaccharide. |
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| What have some types of bacteria developed to deal with dehydration? |
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| glycocalyx (slime layer and capsule) |
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| What are the functions of glycocalyx(capsule and slime layer)? |
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| They aid in attachment to surfaces. 2. They prevent phagocytosis by WBC which increases the bacteria’s pathogenicity. (capsule slide in lab) 3. They protect the bacteria from dehydration. |
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| Endocytosis |
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| Solely eukaryotic-active transport-substances surrounded by pseudopodia and brought into the cell |
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| Exocytosis |
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| Solely eukaryotic process-reverse of endocytosis-enables wastes and secretions to be exported from the cell |
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| How are Mitochondria different from Chloroplasts? |
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| Mitochondria function in aerobic ATP production and chloroplasts function in photosynthesis. |
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| What are the major tenants of the endosymbionic theory? |
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| 1) Eukaryotes are formed from the union of small aerobic prokaryotes with larger anaerobic prokaryotes. 2)Parasites eventually lose the ability to exist independently, but retain a portion of their DNA, some ribosomes and their cytoplasmic membranes. 3)Aerobic prokaryotes eventually evolved into mitocondria and their cytoplasmic membranes became cristae. |
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| What is another way to explain what the endosymbiotic Theory is? |
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| It's a theory where the mitochondria and chloroplasts of the cell are believed to have evolved from bacteria, because they have their own DNA and ribosomes (which is very similar to the bacteria that scientists believe the they evolved from) and reproduce like bacteria. Scientists believe this happened because the cell and the ancient bacteria that the two organelles evolved from transitioned into "endosymbiotic living" (which basically just means that two organisms that aren't the same species live in close association). |
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| What are the functions of the Eukaryotic cytoskeleton? |
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| anchors organelles gives shape to the cell performs endocytosis aids in contraction of the cell |
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| Which stain originated as a specific method to detect Mycobacterium tuberculosis in specimens? |
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| Acid Fast Stains |
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| what do Acid Fast stains do for us? |
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| They detect myobacterium that the gram stain cannot because the cell walls of myobacterium are composed of waxy materials that repel the water based dyes of the Gram stain. |
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| Why do microbiologists stain thier specimens? |
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| to create contrast. |
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| Staining cells increases contrast but the procedure requires that the cells are what? |
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| killed. |
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| What are some examples of dyes used for staining? Name 3 |
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| Methylene blue, crystal violet, and saffranin |
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| Positive stains |
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| Dye sticks to cells (specimen) Gives the bacterial cell color against a bright background. |
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| Examples of dyes used in Positive staining: |
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| Crystal violet Methylene blue Malachite green Safranin. |
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| Negative stains |
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| Dye does not stick to the cell or a structure of a cell Dye settles around its outer boundary of the cell or structure forming a silhouette or “dark cloud”. |
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| Negative stains |
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| The glass slide is stained with the dye The bacteria do not take up the stain and remains white or colorless The bacterial structure does not take up the stain and remains white or colorless |
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| Some dyes used in negative staining: |
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| Nigrosin = black stain India ink = pink stain |
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| Types of Stain include: |
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| Simple stains Special stains Differential stains |
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| Simple stains are |
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| positive stains that use only one dye such as methylene blue or crystal violet. |
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| What are simple stains used to do? |
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| reveal size, morphology and arrangement of cells |
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| What results occur during a simple stain? |
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| Uniform purple stain Uniform blue stain |
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| Differential stains |
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| Use two dyes or more dyes to see: Differences between cells Differences between cell structures. |
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| Differential stains Include |
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| Gram stain Acid-fast stain Endospore stain. |
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| Gram Staining shows differences between |
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| thicknesses of peptidoglycan in bacteria’s cell wall That is all a Gram stain does!! |
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| Why do We Perform Gram Stains? |
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| Bacteria with a thick layer of PG stain purple = gram positive cells. Certain antibiotics work only on Gram + |
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| Why do We Perform Gram Stains? |
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| Bacteria with a thin layer of PG stain red (pink) = gram negative cells. Certain other antibiotics work only on Gram – |
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| Gram negative (–) bacteria contain |
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| Lipid A which is on their lipopolysaccharide(LPS) outer membrane |
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| What is Lipid A |
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| Lipid A is an endotoxin that is released when Gram – bacteria die. |
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| Lipid A may trigger: |
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| Fever Vasodilation Shock Inflammation Blood clotting in humans Release of toxin is what harms human Cause for concern with Gram – pathogens. |
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| Acid Fast Stains (Ziehl-Neelson) |
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| Originated as a specific method to detect Mycobacterium tuberculosis in specimens |
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| Acid fast stains detect |
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| Mycobacterium tuberculosis causes TB or Consumption. Mycobacterium leprae causes Hansen’s disease Mycobacterium bovis causes Bovine TB |
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| Endospore Stains (Shaeffer-Fulton) |
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| Stains are used to detect endospores Dye is forced by HEAT into resistant bodies called endospores. |
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| What is the primary stain in Endospore Stains? |
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| Malachite green is the primary stain |
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| What is the counter stain in Endospore stains? |
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| safranin |
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| Special Stains are |
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| simple stains used to show special structures on the microbe |
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| Special stains include |
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| Flagellar stains Negative stains Fluorescent stains. |
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| Flagellar stains are used to reveal |
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| flagella. |
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| Flagella filaments are so thin that they can only be seen with an |
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| electron microscope. |
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| Flagella can only be seen with a light microscope after a |
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| flagellar stain. |
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| The flagellar stain enlarges the filament by depositing a |
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| coating of the stain on the flagella. |
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| Gram stain results that are pink are |
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| gram negative cells |
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| Gram stain results that are purple are |
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| Gram positive cells |
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| Which stains use heat to drive the stain in? |
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| Acid fast stains and endospore stains |
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| Carl Woese developed a system of |
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| Three Domains. (super-kingdoms) 1980s |
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| Carl Woese Domains were based on the sequence of |
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| DNA nucleotides that code for rRNA. |
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| Robert Whittaker proposed a system (1969) that recognized |
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| Five Kingdoms: Plant Animal Fungi Protist (protozoa) Monera (bacteria). |
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| What is the Domain System? |
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| Eukarya Bacteria Archaea |
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| what process uses refraction of light to make the apparent size of an object larger? |
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| Magnification |
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| Is there are consensus between taxonomists? |
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| No |
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| What does the term growth in microbiology mean? |
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| an increase in the number of microbial cells. |
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| The first true vaccine protected humans against what type of organism? |
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| Virus |
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| Endospores survive a variety of harsh conditions in part because of the presence of |
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| dipicolinic acid |
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| Hetero = |
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| other |
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| Auto = |
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| self |
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| Trophe = |
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| nutrition |
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| Photos = |
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| light |
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| Autotrophs = |
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| feed self, nutrition feed themselves, self feeders, automatic. Plants are also examples of autotrophs. |
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| Autotrophs obtain carbon atoms from |
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| CO2 and make their own organic compounds like plants |
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| Heterotrophs = |
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| eat other, nutrition different (other) feeders. |
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| Heterotrophs obtain carbon atoms from |
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| organic compounds from other organisms like animals (humans) |
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| Heterotrophs are |
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| Animals (humans) |
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| Heterotrophs breakdown other organism’s proteins, carbohydrates, fatty acids, and amino acid and use those Carbon atoms to |
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| make their own organic compounds. |
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| Microbes are categorized into which two groups based on whether they use chemicals or light as source of energy? |
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| Chemotrophs use chemicals for energy (we use chemical glucose) Phototrophs use light for energy |
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| Chemotrophs are_____ that acquire energy from chemical reactions involving inorganic and organic chemicals. |
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| Bacteria |
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| Who are chemotrophs? |
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| Humans |
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| Examples of Chemotrophs |
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| Animals Fungi Protozoa Bacteria Archaea. |
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| Phototrophs are bacteria that acquire energy from |
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| sun. |
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| Examples of Phototrophs |
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| Photosynthetic archaea = cyanobacteria. Annabeana Plants and algae are phototrophs. |
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| Type of organism: Photoautotroph Energy Source=? Carbon source=? |
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| sunlight, CO2 |
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| Type of organism: Photoheterotrophs Energy Source=? Carbon source=? |
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| sunlight, organic compds |
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| Type of organism: Chemoautotrophs Energy Source=? Carbon source=? |
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| inorganic compounds, CO2 |
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| Type of organism: Chemoheterotroph Energy Source=? Carbon source=? |
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| organic compounds, organic compds |
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| Sputum |
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| Sputum is mucus that is coughed up from the lower airways |
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| obligate aerobes |
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| Oxygen is essential |
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| obligate anaerobes |
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| Oxygen is deadly for them |
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| Obligate Aerobes use aerobic metabolism which has an absolute requirement for |
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| oxygen. |
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| grow better in presence of O2 but can grow without O2. |
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| Facultative Anaerobes |
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| Facultative Anaerobes use _____ metabolism and grow best in presence of O2 but can grow in its absence. |
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| aerobic |
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| require just a small amount of O2 from 2-10%. |
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| Microaerophiles |
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| Obligate (strict) Anaerobes |
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| cannot grow if O2 is present. Ex. Clostridia The presence of O2 often kills bacteria |
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| They do not use aerobic metabolism They cannot multiply if O2 is present They are often killed in the present of O2 |
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| Obligate (strict) Anaerobes |
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| They cannot use O2 but tolerate it fairly well. |
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| Aerotolerant anaerobes are anaerobic bacteria |
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| Aerotolerant anaerobes can tolerate O2 and can grow in the presence of oxygen because |
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| They have enzymes that detoxify oxygen’s poisonous forms. |
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| What are endospores? |
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| A resistant asexual spore that develops inside some bacteria cells. (does not reproduce) |
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| How are endospores formed? 8 step process |
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| 1)Vegetative cell's DNA is replicated 2)DNA aligns along long axis 3)cytoplasmic membrane invaginates to form forespore 4)Second membrane forms around the forespore and the vegetative cell's DNA disintegrates. 5) Calcium and dipicolinic acid is deposited between the first and second membranes. 6)Spore coat forms around endospore 7) Spore coat maturation complete. Results in an increase in resistance to heat and chemicals. 8) Endospore released from original cell |
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| Two types of Microscopes: |
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| Simple microscope Compound Microscope |
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| Simple microscope = |
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| one lens = magnifying glass |
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| Compound Microscope have |
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| two lens: objective lens and an ocular lens |
