BACTERIAL ENZYMES Flashcards
What are the enzymes called that accomplish in splitting/breaking down large complex molecules of polysaccharides, proteins or lipids? (They also do this thru hydrolysis)
Extracellular
How are the extracellular enzymes accomplish the breakdown of their respective substrates?
Hydrolysis
T or F:
Carbohydrases such as amylase hydrolyze polysaccharides to sugars
TRUE
T/F:
Proteases hydrolyze lipids to lipoic acids and peptides
FALSE, proteases hydrolyze proteins to peptides and amino acids
What do lipases hydrolyze lipids to?
Lipases hydrolyzes lipids to glycerol and fatty acids
What evidence is obtained when organisms are grown in a medium containing one of the substrates (carbohydrases/proteases/ lipases)
Evidence of degradation
What are the examples of endoenzymes?
Catalase and oxidase
T/F:
Does catalase act on hydrogen peroxide to break down into hydrogen and oxygen?
TRUE
What are the oxidative end product of aerobic respiration (catalase)?
H2O and O2
What are the broth cultures used for the bacterial enzyme experiment?
Escherichia coli, Pseudomonas aeruginosa (lvl 2), Bacillus subtilis
What are the 3 agar plates used for the bacterial enzymes?
Starch (carbohydrates), Tween 80 (fat), skim milk (protein)
T/F:
Oxidase activates the ocidation of reduced cytochrome c by molecular oxygen in aerobic organisms during electron transport
TRUE
What is the result of iodine in the presence of starch?
formation of a dark blue-black colour
For the evidence of carbohydrase (amylase), what will appear if the starch has been hydrolyzed by the production of amylase?
clear zone will appear surrounding the growth of organisms
Does the hydrolysis of lipids, leading to the production of glycerol and fatty acids, result in the formation of a precipitate that causes cloudiness or turbidity?
Yes
What is the formation of precipitate, which will be cloudy or turbid, mean?
The products (fatty acid and glycerol) of hydrolysis of the lipid result
What is a casein?
Casein is the principal nitrogenous (protein) constituent in milk
What is the casein responsible for, and how does it exist?
It exists in a collodial state and is responsible for the whiteness of milk
A milk agar when a protease is hydrolyzed (casein), shows a soluble product and a ____ will surround the streak of bacterial growth
zones of clearing/clear zone
Exoenzyme Activity:
What are the results of starch hydrolysis, lipolysis, and proteolysis
* E.coli
* B. subtilis
* P. aeruginosa
- -ve for E.coli
- +ve for B. subtilis
- -ve, +ve, +ve for P. aeruginosa
What reagent was used to develop a purple to black colour
tetramethyl-p-phenylenediamine reagent
or Oxidase reagent
Endoenzyme activity
what are the types of organisms that had presence of enzyme in catalase?
E.coli, B. subtilis, and P. aeruginosa
what are the types of organisms that had absence of enzyme in oxidase?
E.coli and B. subtilis
What is the difference between an endoenzyme and exoenzyme?
Endoenzyme - the ones that work inside the cell and carry out intracellular biochemical reactions
Exoenzymes - proteins enzymes that work outside the cell
What is the substrate of the catalase reaction? Why are bubbles produced in a positive catalase test?
the substrate of the catalase reaction is hydrogen peroxide and bubbles are produced because of the oxygen gas
T/F:
If catalase is very active due to an abundance of hydrogen peroxide, bubbles are produced.
TRUE
How do the methods for the detection of hydrolysis differ between these 3 tests (bacterial enzymes)
- Casein: uses clear zone to determinepositive & negative
- Starch : adds gram iodine to determine
- Lipids : resulting in products of glycerol and fatty acid with formation of precipitate that will be cloudy/turbid
Which of the following is indicative of lipase activity on Tween 80 agar?
Turbid/cloudy medium
Which of the following organisms has oxidase activity?
Pseudomonas aeruginosa
