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41 Cards in this Set
- Front
- Back
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Name two medically important genera or bacteria that produce endospores
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Bacillus and Clostridium
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Bacillus is Aerobic or Anaerobic?
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Aerobic
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Clostridium is Aerobic or Anaerobic?
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Anaerobic
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What shape is Bacilli?
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rod shaped
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What shape is Cocci?
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sphere shaped
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Gram stain separates almost all bacteria into what two large groups?
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Gram-positive and Gram-negative
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What type of Gram stain is blue?
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Gram positive
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What type of Gram stain is pink?
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Gram Negative
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Why are Gram stains different?
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Because their cell wall compositions are different
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What are the three stains used in the Gram stain procedure?
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Crystal violet
Gram's iodine Safranin |
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What is used to decolorize the cells in the Gram stain procedure?
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Acetone-Alcohol
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How many dyes are used in a simple stain?
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One, methylene blue, basic fuchsin, or crystal violet
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Simple stains allow one to distinguish the _______ of the bacteria.
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shape
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Differential stains are more complex than simple ones and use (one/more than one) stain to differentiate cellular components.
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more than one
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Differential stains are used to examine _______ of bacterial groups.
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structures
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What is the purpose of heat-fixing a bacterial smear?
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To prevent the microorganism from being washed off from the slide.
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List, in order, the reagents used in the traditional gram stain procedure.
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Crystal violet, Gram's Iodine, Acetone-alcohol, and Safranin
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Function of Crystal Violet:
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Primary Stain
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Function of Gram's Iodine:
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Mordant (binds to Gram + = purple color)
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Function of Acetone-Alcohol
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Decolorizer
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Function of Safrinin:
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Counter-Stain (Pink Color)
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Cultures more than _____ hours old may lose their ability to _____ the crystal violet-iodine complex.
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24 hours / retain
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If the decolorizer is left on too long, what will happen?
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A Gram positive will appear as a Gram negative (pink)
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If the decolorizer is not left on long enough, what will happen?
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A Gram negative will appear as a Gram positive (purple)
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Negative & Positive staining:
What type of staining procedure stains the object or structure you wish to see? |
positive staining
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What type of staining procedure stains everything except what you want to see?
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negative staining (background stain)
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What is the isolation of a single species of a microbe?
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Pure culture
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Microorganisms are everywhere meaning they are _____
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ubiquitous
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What technique is used to prevent or minimize the introduction of undesirable microbes?
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Aseptic technique
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A successful transfer of bacteria into a broth culture will be cloudy, also called ______
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turbid
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Why is it important to cool an inoculating loop before obtaining a bacterial sample?
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A hot loop will kill bacterial sample and create aerosols
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Why is it important to hold the test tube cap with your little finger while taking a bacterial sample?
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So you don't contaminate the cap while working
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Why is it important to get a pinpoint amount of a sample as your inoculum?
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If you get too much inoculum, you will not have sufficient area on the plate to get the diluent needed to separate cells
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Why are agar plates inverted when incubating?
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Moisture will condense in the lid instead of on the agar surface. Moisture is harmful to isolated colony growth
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What is an endospore?
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A small spore formed within the vegetative cells of some bacteria.
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What is a spore?
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a reproductive cell of actinomycetes and fungi
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what is the difference between a spore and a gamete?
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gametes must fuse in pairs in order to create a new individual, whereas spores do not
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What are some diseases caused by spore-forming bacteria: (4)
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anthrax, botulism, gas gangrene, and tetanus.
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state one advantage of using a negative stain versus positive stain
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organism is not heat fixed and will not be severely distorted or damaged
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state another advantage of using a negative stain versus positive stain
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the organism will stand out against contrastingly dark background
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what is the diagnostic value of acid fast stain?
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pathogens retain color even in presence of acid
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