Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
What is Litmus Milk used to test for? |
used to distinguish between different species of bacteria depending on their ability to transform "milk" (lactose) into different metabolic end products |
|
Litmus Milk |
|
|
What are the 2 main ingredients in Litmus Milk that can be metabolized by bacteria? |
litmus cannot be used nutritionally by the bacteria |
|
What are the 4 basic reactions that occur in Litmus Milk? |
|
|
In Litmus Milk what does a pink color result indicate? |
acid production |
|
In Litmus Milk what does a pink and solid white in the lower portion with an immovable clot result indicate? |
acid curd
white indicates that the lower portion of the litmus is reduced |
|
In Litmus Milk what do fissures in the clot indicate? |
gas production occured |
|
In Litmus Milk what does a white colored result indicate? |
reduction of litmus |
|
In Litmus Milk what does a not pink and semisolid clot that is moveable indicate? |
Rennet curd |
|
In Litmus Milk what does a blue colored result indicate? |
alkaline reaction |
|
In Litmus Milk what does clarification of the medium indicate? |
proteolysis occured |
|
If an alkaline reaction occurs in Litmus Milk what would you expect it to look like? |
unchanged or deep blue |
|
If proteolysis occurs in Litmus Milk what would you expect it to look like? |
deep purple band at the top
whey-like brownish translucent medium in the remainder of the tube |
|
If a litmus reduction occurs in Litmus Milk what would you expect it to look like? |
a purple band at the top
the remainder of the tube is white |
|
If lactose fermentation occurs in Litmus Milk what would you expect it to look like? |
pink = acidic |
|
If lactose fermentation followed by reduction occurs in Litmus Milk what would you expect it to look like? |
pink band at the top
the remainder of the tube is white |
|
If lactose fermentation followed by reduction and curd formation occurs in Litmus Milk what would you expect it to look like? |
a pink band at the top
the remainder of the tube is white and solid |
|
If lactose fermentation followed by reduction, curd formation, and gas production occurs in Litmus Milk what would you expect it to look like? |
a pink band at the top
the remainder of the tube is white and solid
there will be fissures in the curd |
|
Which bacteria are able to ferment lactose? |
only bacteria that posses the lac operon |
|
lactose fermentation |
|
|
What is the final product of lactose fermentation? |
lactic acid |
|
What causes a clot or curd to form? |
accumulating acid may cause the casein to precipitate solidifying the medium
can be pink or white depending on the oxidation-reduction status of litmus |
|
What color is reduced litmus? |
white |
|
What color is oxidized litmus? |
purple |
|
What is evidence gas production during fermentation of litmus milk? |
fissures in the curd |
|
proteolysis or peptonization |
occurs when microorganisms break down the milk proteins, mainly casein, to amino acids
produces ammonia alkaline reaction (blue) the medium will loose body because the proteins are hydrolyzed producing a translucent brownish color with a blue band at the top |
|
alkaline reaction |
when the microorganism partially degrades casein into shorter polypeptides
produces ammonia alkaline reaction (blue) ; raises the pH of the medium |
|
What type of inoculation is used in this lab? |
stab inoculation |
|
What are the 5 bacteria used in this lab? |
|