Hydrolysis Of Urea Pg 79-80

Question 1

Urea is a metabolic waste product that is ______ to most living organisms.

Answer 1

Toxic

Question 2

Some microorganisms produce an exoenzyme called ______ which can catalyze the breakdown of urea to ammonia and Co2 gas

Answer 2

Urease

Question 3

Urease
Urea+water————> ? +. ?

Answer 3

Ammonia (2NH3)+carbon dioxide gas (CO2)

Question 4

What type of indicator is included in the urea broth to test for the presence of ammonia (strong base) in the reaction?

Answer 4

Phenol red indicator

Question 5

At pH 6.9 (slightly basic) phenol red turns what color?

Answer 5

Pinkish red

Question 6

If the pH goes even higher, it becomes _________ or _______, indicating a strong basic reaction.

Answer 6

Fuchsia or hot pink

Question 7

At pH 6.8 or lower (acid) it is _______ to ______.

Answer 7

Yellow to gold

Question 8

Determining whether or not microorganisms produce _____ can be helpful in identification.

Answer 8

Urease

Question 9

Bacteria in the genera Proteus, Salmonella, and Shigella are all gram-________, facultative anaerobe, lactose fermenting bacilli.

Answer 9

Negative

Question 10

Proteus, a member of the normal, intestinal flora of humans, produces ____?
______ and _______, intestinal pathogens, do not.

Answer 10

Urease
Salmonella and Shigella

Question 11

How long were the Urea broth tubes supposed to be incubated for at 37 degrees Celsius ?

Answer 11

2-4 days.

Question 12

Hydrolysis of urea results/data:

Answer 12

Medium: urea broth
Substrate: urea
Reagents: (included) Phenol red
Pos. End products: ammonia & CO2
Pos. Appearance: pink
Neg. Appearance: salmon color