EX. 15 | Protein Catabolism, Part 1

0.0(0)
Studied by 0 people
call kaiCall Kai
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
GameKnowt Play
Card Sorting

1/3

encourage image

There's no tags or description

Looks like no tags are added yet.

Last updated 7:21 PM on 4/29/26
Name
Mastery
Learn
Test
Matching
Spaced
Call with Kai

No analytics yet

Send a link to your students to track their progress

4 Terms

1
New cards

3 Main Tests

Gelatin Hydrolysis

Urease Test

Litmus Test

2
New cards

Gelatin Hydrolysis

Purpose

  • Detects if bacteria produce gelatinase (enzyme), which breaks down gelatin into amino acids

Gelatinase

  • Exoenzyme that hydrolyzes gelatin, causes it to stay liquid even when cooled below 20oC

Medium used

  • Nutrient gelatin

Results

  • Positive result: Gelatin remains liquid even after being placed in ice (stays liquefied below 20oC) → gelatinase was produced → bacteria produce gelatinase, which breaks down gelatin into amino acids

  • Negative result: Gelatin re-solidifies / stays solid when cooled in ice → no gelatinase produced → gelatinase is absent → bacteria did not break down the gelatin

3
New cards

Urease Test

Purpose

  • Detects if bacteria produce urease (enzyme), which breaks down urea into ammonia and carbon dioxide

    • Urea agar starts at pH 6.8 (yellow) — any rise in pH from ammonia production shifts it toward fuchsia (hot pink)

Urease

  • An enzyme that liberates ammonia from urea

Urea agar

  • Contains peptone, glucose, urea, and phenol red

Urea

  • Waste product of protein digestion, excreted in urine

Medium used

  • Urea agar

Results:

  • Positive result: Ammonia released → pH rises → Phenol red turns hot pink at pH 8.4

  • Negative result: No color change (phenol red stays yellow at pH 6.8 or below)

    • A positive result indicates a color change from yellow to pink

4
New cards

Litmus Milk Test

Purpose

  • Detects many bacterial activities such as casein hydrolysis, lactose fermentation, and litmus reduction

    • Also determines if a solution is acidic or basic by changing color

Litmus milk

  • Skim milk + litmus indicator, used to detect protein hydrolysis and lactose fermentation

Results:

  • Acid produced → Pink → Meaning that lactose fermentation occurred, which produces lactic acid

  • Alkaline produced → Purple → Meaning that amino acids were catabolized

  • Litmus reduced → White → White color indicates litmus has been reduced, meaning that bacteria consumed dissolved oxygen to create an anaerobic environment, using the litmus as its electron acceptor

  • Peptonization → Clear → Casein fully hydrolyzed to amino acids

  • Coagulation → Curd/solid → Excessive acid caused curd formation

<p><span style="color: yellow;">Purpose</span></p><ul><li><p>Detects many bacterial activities such as casein hydrolysis, lactose fermentation, and litmus reduction</p><ul><li><p>Also determines if a solution is acidic or basic by changing color</p></li></ul></li></ul><div data-type="horizontalRule"><hr></div><p><span style="color: yellow;">Litmus milk</span></p><ul><li><p>Skim milk + litmus indicator, used to detect protein hydrolysis and lactose fermentation<br><br></p></li></ul><p><span style="color: yellow;">Results</span>:</p><ul><li><p><u>Acid produced</u> → Pink → Meaning that lactose fermentation occurred, which produces lactic acid</p></li><li><p><u>Alkaline produced</u> → Purple → Meaning that amino acids were catabolized</p></li><li><p><u>Litmus reduced</u> → White → White color indicates litmus has been reduced, meaning that bacteria consumed dissolved oxygen to create an anaerobic environment, using the litmus as its electron acceptor</p></li><li><p><u>Peptonization</u> → Clear → Casein fully hydrolyzed to amino acids</p></li><li><p><u>Coagulation</u> → Curd/solid → Excessive acid caused curd formation</p></li></ul><p></p>