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48 Cards in this Set
- Front
- Back
aerotolerance
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the ability or inability of an organism to grow in the presence of oxygen
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Obligate (strict) aerobes
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Need oxygen
seen at the top of the medium |
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Facultative anaerobes
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Can grow in the presence or absence of oxygen
live throughout the medium |
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Aerotolerant anaerobes
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Respire anaerobically even in the presence of oxygen
live throughout the medium |
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Microaerophiles
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Can live only in environment containing lower than atmospheric levels of oxygen
live near the middle of the medium |
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Obligate (strict) anaerobes
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No oxygen-even small amounts of O2 are lethal
typically live in the lower half to two-thirds of the medium |
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Capnophiles
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Can survive only if CO2 levels are elevated
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Streak Plate technique
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Use a four streak pattern in quadrants, sterilizing the loop for each pass.
Allows for individual cells or colony forming units to separate and grow into individual pure colonies |
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Simple Stain
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Most bacteria have a negative charge. The stains Methyl Blue, Crystal Violet and Safranin will form a bond.
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Heat Fix
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Kills the bacteria
Causes bacteria to adhere to the slide Coagulates the cytoplasmic proteins. |
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Negative Stain
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To determine morphology and cellular arrangement.
The dye and bacteria are both negative charge so the bacteria repels the dye and remains unstained against the dark background Nygrosin and Congo Red |
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Morphology
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Cell shape and arrangement
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Cocci (singular)
Coccus |
Round sphere shape
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Bacilli (singular)
Bacillus |
Rods
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Spirilla (singular)
Spirillum |
Spiral shape
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Vibrios
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Slightly curved rods
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Coccobacilli
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Short rods
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Spirochetes
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flexible sprials
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Pleomorphism
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Variety of cell shapes
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Diplococcus
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two cocci daughter cells remain attached
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Diplobacilli
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two bacilli daughter cells remain attached
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Streptococcus
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a coccus chain
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Streptobacillius
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Bacillus chain
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Tetrad
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Group of four cells (cocci only)
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Sarcina
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Group of eight cells (cocci only)
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Staphyloccus
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cluster of coccus cells
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Gram Stain
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A method of staining that differentiates between Gram (-) and Gram (+) bacteria. The results of this stain depend upon the cell wall of the bacterium.
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Gram Stain's 4 reagents in order
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Primary Stain - Crystal Violet
Mordant - Gram's Iodine Decolorizing Agent - 95% Ethanol Counterstain - Safranin |
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In Gram Staining, what is the purpose for the Ethanol?
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Decolorizing Agent; the most critical step of Gram staining.
It is a lipid solvent, so the outer membrane of the Gram negative bacteria will melt away and washes out the dark purple stain and leaves the Gram negative bacteria colorless. |
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When Gram Staining what is the purpose of Safranin?
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Because the outer membrane of the Gram negative bacteria has been melted away and the purple is gone, safranin will stain the Gram (+) cells pink.
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Acid Fast Stain shows this
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Use to detect cells capable of retaining a primary stain when treated with an acid alcohol. Used to identify Mycobacterium
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Mycobacterium
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Have Mycolic Acid in the cell wall (a waxy substance)
Use the Acid Fast Stain to identify |
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Endospore Stain
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Use to detect the presence of spores in bacterial cells
Smear, air dry, heat fix With steam and Malachite green flood for 5-7 min Rinse Flood with Safrinin 1-2 min Rinse; blot |
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Endospore
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a dormant stage of bacteria to survive in a poor environment
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Hanging Drop stain
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To observe Motility (flagella), a wet mount preparation on a special slide (has a depression) with a cover slip. A drop of water is placed on the cover slip (four corners have a thin dot of petroleum jelly) the microbe is transferred to the cover slip. NO STAIN IS USED
Invert the slide for viewing |
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Catalase Test
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To identify organisms that produce the enzyme catalase, used to break down H2O2 into H2O + O2
(+) shows gas (O2) |
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Citrate Test
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Test for possession of the enzyme Citrate-permease allows the organism to use citrate as a sole carbon source
Green medium changes to blue in (+) pH 7.6 or higher |
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Fermentation; Starch Hydrolysis
Glucose |
If an organism can use glucose to produce pyruvate by glycolysis
Clear halo around colony (+) Amylase enzyme |
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Gelatinase Test
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Ability to produce gelatinases
Watery tube (+) solidification of media (-) (-) is the presence of gelatinase enzyme to hydrolyze gelatin |
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Indole Test
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produce indole using enzyme tryptophanase
SIM method test for motility, NH3, and Indole Add Kovak's Reagent which will react with the indole to produce quinoidal compound Red= (+) bacteria has the enzyme No Red = indole (-) |
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Lipase Test (egg yolk)
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Lipid Hydrolysis (lipids are fats)
Lipases can hydorlyze fat, they break down the Triglycerides (glycerol + 3 Fatty Acid chains) Pink = (-) Clear zones =(+) |
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Methyl Red/Vogues Proskauer Test
MR-VP |
A combination test to detect an organism capable of overcoming the buffer and lowering the pH
Red = (+) Oranges and Yellows =(-) |
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Motility Test
(H2S ?) |
Stab with a straight needle.
(+) shows diffuse growth radiating from the central stabline |
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Starch Hydrolysis
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Ability to hydrolyze starch, enzyme amylase or glucosidase
Breaks down starch to get it into the cell (+) clear zones (-) blue/dk brown |
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Urease Test
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ability to hydrolyze urea with urease break it into NH3 + CO2
Proteus have rapid urease activity (can cause urinary infection) (+) pink |
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Two differential stains
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Gram Stain
Acid Fast Stain |
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List the steps of Acid Fast Stain
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Do smear, air dry, heat fix
Steam Fix with Carbol Fuchsin for 5-7 minutes Rinse Rinse with Acid Alcohol 1 min flood with Methyl Blue 1-2 min blot (+) pink are acid fast (-) blue |
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describe the negative stain smear method for Capsular Staining
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put a drop of the bacteria toward the end of a clean slide.
put the ink (Nigrosin) a bit further toward the end. use a second clean slide to drag first across the ink then adding the bacteria as you drag without stopping |