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196 Cards in this Set
- Front
- Back
T-Soy Agar is used to grow _
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normal heterotrophic bacteria;
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SDA is used to grow _
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Sabouraud's Dextrose Agar- used for growing fungi;
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What prevents bacterial growth on SDA?
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Its low pH
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Enrichment-type Agars are used for growing _
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Fastidious microbes
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Selective-type Agars are used for _
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Allowing the growth of some type of microbes while inhibiting the growth of another type.
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Differential-type Agars _
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Contain dyes and indicators which color different bacterias
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Blood Agar is __% Vertebrate whole blood?
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6-10%
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To create blood agar, the blood is added to melted agar and cooled to
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45-50°C
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Blood agar is used to grow
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bacteria who need the nutrients found in vertebrate blood
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Blood agar is used to detect
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Hemolysis by bacteria
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If Staph. aureus was cultured on blood agar, which bacterial process would be able to be detected?
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Hemolysis
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Chocolate agar is _% Vertebrate whole blood
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5-10%
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When making chocolate agar, the blood is added to nutrient agar and cooled to _
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80°C
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Blood Agar is which type of agar?
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Enrichment
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Chocolate Agar is which type?
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Enrichment
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One advantage of using chocolate agar over blood agar is _
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Chocolate agar has a longer shelf life
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Why does chocolate agar appear brown?
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The blood cells are lysed
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Staphylococcus medium no. 110 is which type of agar?
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Selective
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Staphylococcus medium no. 110 is used for growing ?
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Halophiles
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What ingredient in Staphylococcus medium no. 110 allows for Halophiles to grow easily?
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NaCl
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What percentage of NaCl is added to create Staphylococcus medium no. 110?
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7.5%
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Brilliant Green Agar is which type?
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Selective
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Brilliant Green Agar allows for the growth of?
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Salmonella
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What is added to Brilliant Green Agar?
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Brilliant Green dye
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how will Salmonella colonies appear on Brilliant Green agar?
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Pink surrounded by a bright red
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Bacteria other than salmonella may grow on brilliant green agar if they ferment ________ or _____
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lactose or sucrose
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Bacteria colonies other than salmonella growing on brilliant green agar will appear _____
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Surrounded with a yellow-green hue
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Transgrow agar is which type
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Selective
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Transgrow agar is used to grow ___
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Niesseria gonorrhoea
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What are the components of transgrow agar?
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Chocolate agar + 3 antibiotics
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Transgrow agar is usually grown in
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a screwcap bottle
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Why is transgrow agar grown in a screwcap bottle?
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**********************Awaiting answer**
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EMB Agar is which type?
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Differential
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EMB Agar is used to determine
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if sucrose and lactose are fermented or not
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EMB agar is enriched with
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Sucrose and lactose
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Which stains are added to EMB agar?
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Methylene blue and Eosin
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Bacterial colonies grown on EMB agar that ferment sucrose and lactose will appear
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purple with a green sheen
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MacConkey Agar is which type?
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Differential
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MacConkey agar is used to ____
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Distinguish between pathogenic salmonella and non-pathogens present in feces or urine
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MacConkey agar is made of nutrient agar with ___________ added
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Neutral red dye
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MacConkey agar prevents this type of bacteria from growing
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Gram (+)
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Coliform bacteria grown on MacConkey agar will appear ___
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Red or pinkish
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Pathogenic salmonella grown on MacConkey agar will appear ____
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clear
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What is the purpose of the streak plate and pour plate methods?
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To isolate pure colonies from a mixture of bacterial species
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When growing anaerobes, would you use the streak plate or pour plate method?
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Pour plate
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Place loopful on plate, pull 3 or 4 lines, flame, without re-inoculating, drag 3 or 4 lines through those lines, flame, This method is known as
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Radiant streak method
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Mixing bacterial mixtures in melted agar, transferring some from the previous tube into the next, and then pouring each tube into a petri dish.
This method is known as |
Pour plate method
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In the radiant streak experiment, pure colonies were most easily found where?
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the last set of streaks made
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The experiment "Effect of Incubation Temp. on microbial growth" demonstrated that ____ is the optimum incubation temperature for bacteria and fungi
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36°C
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In the effect of incubation temperature on microbial growth lab, why was Bacillus thurengesis the only species to show growth after incubation at 100°C?
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It forms spores which protect it from the heat
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at <0°C, bacterial growth is ____
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slowed (not stopped)
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Thermophiles
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Microbes which thrive in high temperatures
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Mesophiles
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Prefer room-temp/ moderate temp. (like 36°C)
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Psychrophiles
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Prefer colder temps
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In the thermal death point lab, after placing the tube of bacteria in it's designated temperature for 10 minutes, it was placed into an ice bath. Why?
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To stop the heating effect on the bacteria
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When determining if bacterial growth is present in a nutrient broth, what 3 things do you need to look for?
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Pellicle, sediment, and turbidity
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Pellicle
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A clump of bacteria floating at the top of a nutrient broth
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Sediment
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A clump of bacteria that has settled to the bottom of a tube of nutrient broth
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Turbidity
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bacteria visibly suspended throughout the nutrient broth
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The osmotic gradient of a solution is manipulated by
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adding different concentrations of solute
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The Swab technique
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"Paint" The entire surface of the agar with the culture (up & down squiggles then left and right squiggles
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Solute
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Solid- in osmotic gradient lab, either sugar or NaCl
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Solvent
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Liquid- in osmotic gradient lab, it was nutrient agar
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Increased amount of solute = _____ osmotic pressure
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increased
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An increased osmotic pressure makes water _____ available to bacteria
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Less
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Can fungi or bacteria grow better in a higher osmotic pressure environment?
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Fungi
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Why can fungi grow better in an environment with high osmotic pressure?
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Because they can get water from the atmosphere
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Why is salt a more effective solute than sugar in the osmotic gradient lab?
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The salt breaks into ions when NaCl is dissolved (sugar does not)
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What is a pH indicator?
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A chemical that changes color in response to pH levels
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Phenol red in an acidic environment will be what color?
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Yellow
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Phenol red in a basic environment will be what color?
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Red
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Methyl Red in an acidic environment will be what color?
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Red
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Methyl Red in a basic environment will be what color?
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Yellow
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Three monosaccharides:
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Glucose, Fructose, Galactose
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Glucose, fructose, and galactose all have the same empirical formula. What is the difference between the 3?
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The arrangement of atoms
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All known life forms use only the ___ forms of sugars?
(D-form or L-form) |
D-form
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All known life forms use only the ___ forms of amino acids? (D-form or L-form)
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L-form
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Dextrose is the ___ form of glucose
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D-form (D-Glucose)
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Sucrose=
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Glucose + Fructose
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Lactose=
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Glucose + Galactose
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Maltose=
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Glucose + Glucose
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Sucrose, Lactose, and Maltose are all _____
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Disaccharides
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What materials can block UV Rays as learned in the UV experiment?
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Card stock, clear plastic
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Does UV light kill spores?
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NO
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Did microbes grow where covered with clear plastic and were exposed to UV for 3 minutes?
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Yes, because it blocks UV
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Did microbes grow where exposed to UV for >1 min?
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No, excluding B. cereus
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Did microbes grow when exposed to UV for 30 seconds?
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Most did
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What was the only disinfectant to kill spores in the experiment?
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Formalin
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What is Mueller-Hinton Agar used for?
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Antibiotic sensitivity testing
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What are disinfectants?
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Germicides designed for use on surfaces
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What are antiseptics?
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Germicides designed for use on living tissue
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What is a zone of inhibition?
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A clear circle around an antibiotic sensitivity disc where bacteria did not grow.
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What does a zone of inhibition conclude?
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The effectiveness of an antibiotic
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To test for hydrolysis of starch, what medium is used?
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Starch agar
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To test for hydrolysis of starch, what is the end product
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simple sugar
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To test for hydrolysis of starch, what is the reagent
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iodine
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To test for hydrolysis of starch, what is a positive result
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unchanged
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To test for hydrolysis of starch, what is a negative result
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dark purple color around colonies
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To test for hydrolysis of Caesin, what medium is used
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skim milk agar
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To test for hydrolysis of Caesin, what is the reagent
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None
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To test for hydrolysis of Caesin, what is the end product?
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single amino acids
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To test for hydrolysis of Caesin, what is a positive result?
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Clear around bacterial colonies
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To test for hydrolysis of Caesin, what is a negative result
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Opaque around colonies
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What is caesin?
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milk protein
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In testing for hydrolysis of lipids, what medium is used?
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Spirit blue agar
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In testing for hydrolysis of lipids, what is the reagent
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lipase reagent
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In testing for hydrolysis of lipids, what is the end product?
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glycerol & fatty acid
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In testing for hydrolysis of lipids, what is a + result?
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Dark blue percipitate areound colonies
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In testing for hydrolysis of lipids, what is a negative result?
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No precipitate
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In testing for hydrolysis of Tryptophane, what medium is used?
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T-soy broth
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In testing for hydrolysis of Tryptophane, what is the end product?
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Indole
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In testing for hydrolysis of Tryptophane, what is the reagent?
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Kovac's reagent
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In testing for hydrolysis of Tryptophane, what is a positive result?
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Red at top of tube
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In testing for hydrolysis of Tryptophane, what is a negative result?
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Medium unchaged
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In testing for hydrolysis of urea, what medium is used?
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urea broth
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In testing for hydrolysis of urea, what is the end product?
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ammonia
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In testing for hydrolysis of urea, what reagent is used?
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Phenol red
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In testing for hydrolysis of urea, what is a positive result?
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Medium turns red
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In testing for hydrolysis of urea, what is a negative resuly?
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medium orange-yellow
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IN testing for reduction of Sodium Thisulfate, what medium is used?
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Triple sugar iron agar
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IN testing for reduction of Sodium Thisulfate, what reagent is used?
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Iron sulfate
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IN testing for reduction of Sodium Thisulfate, what is the end product?
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Hydrogen sulfide (H2S)
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IN testing for reduction of Sodium Thisulfate, what is a positive result?
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Medium turns black
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IN testing for reduction of Sodium Thisulfate, what is a negative result?
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medium does not turn black
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In testing for oxidation of citrate, what medium is used?
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Simmon's citrate agar
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In testing for oxidation of citrate, what reagent is used?
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Brom Thymol Blue
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In testing for oxidation of citrate, what is the end product
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Alkali
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In testing for oxidation of citrate, what is a positive result?
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Blue medium
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In testing for oxidation of citrate, what is a negative result?
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Green medium
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In testing for coagulation of casein, what medium is used?
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Litmus milk broth
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In testing for coagulation of casein, what reagent is used?
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None
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In testing for coagulation of casein, what is the end product?
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Curds
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In testing for coagulation of casein, what is a positive result?
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Curds present
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In testing for coagulation of casein, what is a negative result?
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no curds
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In testing for fermentation of glucose, which two mediums can be used?
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MR-VP or Phenol Red broth
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In testing for fermentation of glucose, the end product is?
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Acid/ acid + gas
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In testing for fermentation of glucose when using Phenol Red broth, what reagent is used?
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Phenol Red
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In testing for fermentation of glucose when using Phenol Red broth, what is a positive result?
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Yellow medium, gas in durham tube
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In testing for fermentation of glucose when using Phenol Red broth, what is a negative result?
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Red medium, no gas in durham tube
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In testing for fermentation of glucose when using MRVP Medium, what reagent is used?
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Methyl Red
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In testing for fermentation of glucose when using MRVP Medium, what is a positive result?
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Red medium
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In testing for fermentation of glucose when using MRVP Medium, what is a negative result
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yellow medium
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When testing for fermentation of sucrose, what medium is used?
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Phenol Red broth
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When testing for fermentation of sucrose, what reagent is used?
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Phenol red
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When testing for fermentation of sucrose, what is the end product?
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acid
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When testing for fermentation of sucrose, what is a positive result?
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Yellow + gas in durham tube
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When testing for fermentation of sucrose, what is a negative result?
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red, no gas in durham tube
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When testing for fermentation of lactose, what two media can be used?
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Litmus milk broth or phenol red broth
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When testing for fermentation of lactose, what is the end product?
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Acid
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When testing for fermentation of lactose using litmus milk broth, what reagent is used?
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Blue litmus
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When testing for fermentation of lactose using litmus milk broth, what is a positive result?
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Pink medium
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When testing for fermentation of lactose using litmus milk broth, what is a negative result?
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unchanged medium
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When testing for fermentation of lactose using phenol red broth, what reagent is used?
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Phenol red
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When testing for fermentation of lactose using phenol red broth, what is a positive result?
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Yellow, gas in durham tube
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When testing for fermentation of lactose using phenol red broth, what is a negative result?
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Red, no gas
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When testing for aerobic oxidation of glucose, what medium is used?
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MRVP medium
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When testing for aerobic oxidation of glucose, what reagent is used?
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Barrit's A + B
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When testing for aerobic oxidation of glucose, what is the end product?
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Acetocin
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When testing for aerobic oxidation of glucose, what is a positive result?
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pink
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When testing for aerobic oxidation of glucose, what is a negative result?
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Not pink
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When detecting the enzyme catalase, what medium is used?
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T-soy agar slants
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When detecting the enzyme catalase, what is the reagent?
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H2O2 (hydrogen peroxide)
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When detecting the enzyme catalase, what is a positive result?
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Bubbles form
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When detecting the enzyme catalase, what is a negative result?
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No bubbles
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When detecting the enzyme oxidase, what medium is used?
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T-soy agar plate
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When detecting the enzyme oxidase, what reagent is used
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Dry slide
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When detecting the enzyme oxidase, what is a positive result
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purple
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When detecting the enzyme oxidase, what is a negative result
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unchanged
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Liquid thioglycollate medium is useful for determining
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the oxygen requirements of organisms
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Liquid thioglycollate medium will remove what in the medium?
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Oxygen
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When the growth is concentrated at the top of Liquid thioglycollate medium, what can be concluded?
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The organism is an obligate aerobe
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When the growth is concentrated at the bottom of Liquid thioglycollate medium, what can be concluded?
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The organism is an obligate anareobe
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When the growth is concentrated at the top of Liquid thioglycollate medium and less concentrated towards the bottom, what can be concluded?
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The organism is a facultative anaerobe
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When the growth is even throughout Liquid thioglycollate medium, what can be concluded?
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the organism is an aerotolerant anaerobe
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blood agar is useful for growing what specific type of pathogen?
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urinary pathogens
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What temp. does agar solidify at?
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42 C
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Desoxycholate lactose agar DLA Agar is what type?
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Selective
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Desoxycholate lactose agar (DLA) selects FOR
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Gram (-) bacteria
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Desoxycholate lactose agar selects against
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Gram (+) organisms
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PEA-B Selects against
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Gram (-)
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PEA-B Selects for
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Gram (+)
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Lactobacillus count method
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Determines # of lactobacillus cells/ml of saliva
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What medium is used when selecting for acid-tolerant bacterial species in saliva?
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Rogosa SL Agar
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Lactobacillus and strep. mutans are ?
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acidophiles
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How is the # of lactobacillus cells calculated?
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count # of colonies, multiply by reciprocal of dilution
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> 50,000 lactobacillus count is an indicator of ____
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poor oral hygiene, increased susceptibility to dental carries
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What is the lactobacillus activity method?
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Determines carries susceptibilities by determining the rate of acid production by lactobacillus
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Snyder test agar is used for?
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Lactobacillus activity determination
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Snyder test agar selects for
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aero-tolerant bacteria
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Snyder test agar selects against
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non-acidophiles
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What indicator is added to Snyder test agar to indicate changes in pH??
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Bromcersol Green
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Low pH in snyder test agar is displayed by
|
Yellow color
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High pH in snyder test agar is shown by
|
Green color
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Demineralization of tooth enamel begins at what pH?
|
5.5
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If the lactobacillus activity method test shows results within 24hrs, this means
|
highest susceptibility to dental caries
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If the lactobacillus activity method test doesn't show results within 72 hours, this means
|
there is no risk of dental caries
|