Final Flashcards
Obligate aerobes
require oxygen and will only grow at the top of the medium
Obligate anaerobes
are harmed by oxygen and will only grow at the bottom of the medium
Facultative anaerobes
grow in the presence and absence of oxygen and are more prevalent at the top of the broth (where the oxygen is) but will grow throughout the medium
Microaerophiles
only survive in less than atmospheric levels of oxygen but still need a small amount of oxygen. They will grow from the middle to the upper middle region of the medium.
Aerotolerant anaerobes
don’t require oxygen but aren’t harmed by it and will grow uniformly through the medium.
Thioglycollate medium
special broth that has a gradient of oxygen levels. There is a dye called resazurin in it that is pink when oxidized and colorless when it is reduced.
ubiquitous
means they can be found everywhere on our planet
streak plate method
a way to separate bacteria in a mixed culture in order to isolate and subculture single species/types of bacteria into a pure culture
anaerobic jar
permits the growth of anaerobic and facultative bacteria through the use of gas packets
presence of CO2 (anaerobic jar)
Indicator turns from pink to yellow
Blood agar plates
test for pathogenic bacteria
Hemolysins are exotoxins that are able to destroy red blood
Hemoglobin
blood agar is used to test bacteria for
ability of hemolysis.
Beta-hemolysis (β-hemolysis)
complete destruction of red blood cells, and is indicated by a clearing around the growth
Alpha-hemolysis (α-hemolysis)
damaging of the red blood cells (not complete destruction, only partial) and is indicated by a greenish discoloration.
Gamma-hemolysis (γ-hemolysis)
actually nonhemolysis and this is indicated simply by normal growth with no clearing in the agar.
Nitrate broth
differential medium. It is used to determine if an organism is capable of reducing nitrate (NO3- ) to nitrite (NO2-)or other nitrogenous compounds
Simmons citrate medium
used in this test and it contains sodium citrate as the only carbon-containing compound source and ammonium ions as the only nitrogen source.
pH increases,
turns blue, which indicates the bacteria are able to utilize the citrate.
What significance does this test have in relation to microbial metabolism?
The significance of this test shows that only bacteria that had the ability to create enzymes citrate-permease were able to growth, as these enzymes allow citrate to be transported throughout the cell. The microbial metabolism is represented by the change in color (blue) or the indicator of growth.
Voges-Proskauer tests
able to ferment glucose, but then convert the acid products to acetoin and 2,3-butanediol
positive VP test is indicated by
Red
Negative VP test is indicated by
Copper or no change in color
mixed acid fermentation
produce more acid
MR-VP test is used
determine some of those products. (convert the glucose to acids.)
MR-VP broth includes peptone, glucose, and a phosphate buffer.
Amylase
(an enzyme released from the bacteria into its surroundings) that breaks starch by cleaving large starch
Iodine
turns a blue/black color when it comes into contact with starch
amylase is present
clearing in the agar where the iodine did not react with any starch.
Kirby-Bauer method
disk-diffusion method, is a method used to test the effectiveness of antimicrobials against pathogenic microorganisms
