Lab 14 Flashcards
Many carbohydrates– including monosaccharides such as _____, disaccharides such as _____, and polysaccharides such as _____ – can be fermented.
glucose, sucrose, startch
used to detect acid and gas production from carbohydrates
fermentation tube
fermentation that results in acid production will turn the indicator ____ (pH of ___ or below)
yellow, 6.8
during prolonged incubation periods (>24 hrs) many bacteria will begin growing _____ on the peptone after exhausting the carbohydrate supplied, causing ____ of the indicator and turning it red because of _____ production.
oxidatively, neutralization, ammonia
used to distinguish organisms that produce large amounts of acid from glucose and organisms that produce the neutral product acetoin
MRVP broth
MRVP medium in a glucose-supplemented nutrient broth used for what two test?
methyl red (MR) test and Voges-Proskauer (V-P) test
If an organism produces a large amount of organic acid from glucose, the medium will remain ___ when methyl red is added in a _____ MR test, indicating that the pH is ______.
red, positive, below 4.4
Methyl red is ______ between pH 4.4 and 6.0
orange-red
If _____ products are produced, methyl red will turn yellow, indicating a pH _____.
neutral, above 6.0
The production of _____ is detected by the addition of potassium hydroxide and alpha-maphthol.
acetoin
If acetoin is present the upper part of the medium will turn ____; a negative V-P test will turn the medium _______.
red, light brown
Bacteria with the enzyme _____ can break down _____ to from pyruvate, which can be reduced in fermentation.
citratelyase, citrate
The indicator ______ changes to blue when the medium is alkalized, indicating a _____ citrate utilization test.
bromthymol blue, positive
