Lab 7-biochemical testing Flashcards
Biochemical testing is a way of building a biological profile of a microbial species that is helpful
in classifying and identifying the organism.
True
Contamination of pure cultures with additional microbes is a major cause of error in biochemical
testing.
True
Phenol red broth is a biochemical test that tests for a microbe’s ability to metabolize specific
amino acids such as leucine, glycine and serine.
False
All of the biochemical tests we performed could be immediately interpreted after inoculation.
False
Escherichia coli is able to ferment a variety of carbohydrates.
True
Which organism(s) evolved a gas while metabolizing lactose in our lab experiments?
E.coli
Phenol red is ___ in a base and ___ in an acid.
magenta (light red); yellow
What does a yellow colored broth indicate in the phenol red tube experiment?
Carbohydrate fermentation
What is urease?
A bacterial enzyme is required to break down urea
Which microbial test did we do to test for motile organisms?
SIM test
Which biochemical test(s) did we perform to examine a microbe’s ability to catabolize (a)
specific amino acid(s)?
Phenylalanine slants
Which of the following descriptions applies to Bacillus subtilis?
it produces starch hydrolase which breaks down starch and therefore leaves the media clear
when stained with iodine.
e. It produces Phenylalanine d
How do you know a bacteria is non-motile?
organisms will grow only along the line of inoculation (observe the tube at the center)
Proteus vulgaris produces a very dark color when inoculated into SIM medium. What
metabolite does P. vulgaris produce that is responsible for this characteristic?
H2S
The presence of indole indicates the ability of a microbe to do which of the following?
Degrade the amino acid tryptophan
