Question

81% Help % Lab 39 worksheet 25% + Room Add Page Insert Durham Tube Sugar Fermentations Table Chart Text Shape Media Comment 1. Which tube, red or yellow, is positive for sugar fermentation? 2. Is the color change an increase or decrease in pH? 3. Which two gases can be revealed by the bubble in the inverted tube? Mixed Acid (MR test) and Butanediol production (Voges:Proskauer, VP test) 1. Which group of bacteria is the Mixed Acid test particularly useful for? 2. Which color of the reaction in the spot plate (red or yellow) shows the presence of a mixed acid fermenter? is this due to an increase or decrease in pH? 3. What is the name of the end-product detected in the Voges-Proskauer test? 4. If the VP test is positive, will the MR test be positive or negative? Nitrate reduction From the supplements, you can see that there are two sets of steps to follow for the nitrate reduction test. 1. For the first set (beginning with 3 drops of Trommsdorf solution.... does a blue color indicate the presence or absence of nitrate reduction? 2. For the second set (beginning with 1 drop diphenylamine ..), does a blue color indicate the Presence or absence of nitrate reduction? Catalase Production 1. Catalase is an enzyme which degrades which molecule? 2. Is catalase produced by aerobes or anaerobes? 3. The bubbling seen in a positive is likely due to the presence of which gas? Oxidase Test 1. In what stage of cellular respiration does cytochrome oxidase occur? 2. This enzyme transfers electrons to which molecule? 257 words C
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Answer 1

ANSWERS

DURHAMS TUBE SUGAR FERMENTATION

1. Yellow tube is positive for sugar fermentation.
2. Decrease in pH will occur due to the acid production in the medium.
3. Hydrogen or carbon dioxide is formed

MIXED ACID ( MR TEST ) AND BUTANEOL PRODUCTION

1. Enterobacteriaceae is used for mixed acid test.
2. Redcolourshows the presence of mixed acid fermenter , the pH will decrease.
3. It is to detect acidity when an organism ferments glucose.
4. If the culture turns red MR test will be positive and if culture turns yellow MR test will be negative.

CATALASE PRODUCTION

1. catalases degrade hydrogen peroxide to water and oxygen.
2. Catalase is produced by aerobes.
3. It is due to the presence of oxygen gas.