BACTERIAL ENZYMES Flashcards

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1
Q

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)

A

Extracellular

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2
Q

How are the extracellular enzymes accomplish the breakdown of their respective substrates?

A

Hydrolysis

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3
Q

T or F:
Carbohydrases such as amylase hydrolyze polysaccharides to sugars

A

TRUE

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4
Q

T/F:
Proteases hydrolyze lipids to lipoic acids and peptides

A

FALSE, proteases hydrolyze proteins to peptides and amino acids

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5
Q

What do lipases hydrolyze lipids to?

A

Lipases hydrolyzes lipids to glycerol and fatty acids

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6
Q

What evidence is obtained when organisms are grown in a medium containing one of the substrates (carbohydrases/proteases/ lipases)

A

Evidence of degradation

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7
Q

What are the examples of endoenzymes?

A

Catalase and oxidase

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8
Q

T/F:
Does catalase act on hydrogen peroxide to break down into hydrogen and oxygen?

A

TRUE

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9
Q

What are the oxidative end product of aerobic respiration (catalase)?

A

H2O and O2

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10
Q

What are the broth cultures used for the bacterial enzyme experiment?

A

Escherichia coli, Pseudomonas aeruginosa (lvl 2), Bacillus subtilis

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11
Q

What are the 3 agar plates used for the bacterial enzymes?

A

Starch (carbohydrates), Tween 80 (fat), skim milk (protein)

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12
Q

T/F:
Oxidase activates the ocidation of reduced cytochrome c by molecular oxygen in aerobic organisms during electron transport

A

TRUE

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13
Q

What is the result of iodine in the presence of starch?

A

formation of a dark blue-black colour

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14
Q

For the evidence of carbohydrase (amylase), what will appear if the starch has been hydrolyzed by the production of amylase?

A

clear zone will appear surrounding the growth of organisms

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15
Q

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?

A

Yes

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16
Q

What is the formation of precipitate, which will be cloudy or turbid, mean?

A

The products (fatty acid and glycerol) of hydrolysis of the lipid result

17
Q

What is a casein?

A

Casein is the principal nitrogenous (protein) constituent in milk

18
Q

What is the casein responsible for, and how does it exist?

A

It exists in a collodial state and is responsible for the whiteness of milk

19
Q

A milk agar when a protease is hydrolyzed (casein), shows a soluble product and a ____ will surround the streak of bacterial growth

A

zones of clearing/clear zone

20
Q

Exoenzyme Activity:

What are the results of starch hydrolysis, lipolysis, and proteolysis
* E.coli
* B. subtilis
* P. aeruginosa

A
  • -ve for E.coli
  • +ve for B. subtilis
  • -ve, +ve, +ve for P. aeruginosa
21
Q

What reagent was used to develop a purple to black colour

A

tetramethyl-p-phenylenediamine reagent

or Oxidase reagent

22
Q

Endoenzyme activity

what are the types of organisms that had presence of enzyme in catalase?

A

E.coli, B. subtilis, and P. aeruginosa

23
Q

what are the types of organisms that had absence of enzyme in oxidase?

A

E.coli and B. subtilis

24
Q

What is the difference between an endoenzyme and exoenzyme?

A

Endoenzyme - the ones that work inside the cell and carry out intracellular biochemical reactions

Exoenzymes - proteins enzymes that work outside the cell

25
Q

What is the substrate of the catalase reaction? Why are bubbles produced in a positive catalase test?

A

the substrate of the catalase reaction is hydrogen peroxide and bubbles are produced because of the oxygen gas

26
Q

T/F:
If catalase is very active due to an abundance of hydrogen peroxide, bubbles are produced.

A

TRUE

27
Q

How do the methods for the detection of hydrolysis differ between these 3 tests (bacterial enzymes)

A
  • 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
28
Q

Which of the following is indicative of lipase activity on Tween 80 agar?

A

Turbid/cloudy medium

29
Q

Which of the following organisms has oxidase activity?

A

Pseudomonas aeruginosa