MIDTERM 2 - Urea hydrolysis Flashcards Preview

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Flashcards in MIDTERM 2 - Urea hydrolysis Deck (15):

Bacteria Metabolizes carbohydrates for..



Bacteria Metabolizes proteins and amino acids for..

growth and synthesis


What part of the amino acid are secreted when the carbon backbone is taken?

1. Ammonia
2. H2S are extreted.


What can ammonia be converted to by some organisms?

it can be converted to Urea


Where can urea have such high concentrations?

1. in an organisms environment due to urine of higher animals
2. areas of high protein decomposition


Why is Urea a problem?

it can denature proteins and is toxic to microorganisms


What are Ammonia and Urea also by-products of?

They can be by products of nucleic acid decomposition


What is Proteolytic activity?

Hydrolyzing or breakdown of protein


Tests for proteolytic activity?

1. Urease test
2. Kliger Iron Agar Test for H2S production
3. Casein hydrolysis test
4. Gelatin Hydrolysis Test


Significance of Urease?

This enzyme enables an organism to detoxify urea, and to release usable energy as it hydrolyzes it to ammonia and CO2


How does this Urease Hydrolysis Test work?

Ammonia reacts with the water in the medium to produce Ammonium Hydroxide, causing the pH to rise.


What pH indicator does the Urease Hydrolysis test contain and how does it change color? What is its initial pH?

Urea medium contains phenol red indicator in addition to urea, and has an initial pH of about 6.5-6.8.When the released ammonia raises the pH sufficiently, the color of the phenol red changes to a magenta/cherry pink


What increases the pH of the Urea medium?

Hydrolysis of urea produces ammonia that increases the pH


Whats special about the sensitivity of the urea medium that accommodates for species that produces a small amount of urease?

its buffered and contains certain nutrients that increase the sensitivity of the test


pH values at which color changes in urease test?

Light Orange at pH 6.8
Magenta at pH 8.1