Fermentations are energy producing biochemical reactions in which organic molecu

Question

Fermentations are energy producing biochemical reactions in which organic molecules can serve as both electron acceptors and donors. The ability of a microorganism to ferment various carbohydrates as well as the types of products formed can be very useful in the identification of the microorganism. In a Wright's tube, pyrogallol and NaOH serve to provide a sterile environment for the microbes to grow. In Brewer's anaerobic agar, the ingredient that removes O_2 from the medium is an oxyrase enzyme. Gene transfer that occurs in bacteria mediated through a viral is called transformation. What is the purpose of the phenol red in the fermentation tubes? a. A source of carbohydrate b. An anti-oxidant c. A pH indicator d. An oxidation-reduction (redox) indicator E coli is a microorganism that uses its beta-galactosidase to ferment lactose. What is the appearance of a lactose-containing Durham tube after inoculating with E coli and incubating at 37 degree C, overnight? (A: acid, G: gas) a. A/G b. A/- d. none of the above What is the function of a Durham tube in the fermentation test? a. To measure acidity b. To measure gas production c. To determine carbohydrate source d. To detect anaerobic response A microorganism's O_2 requirement can be easily seen by inoculating a tube of molten agar with the bacteria in question (mixing the agar thoroughly without agitating it). In the figure below, several bacterial strains were tested in this format. Please fill the blank with proper aerophilic profile of the microorganisms shown in questions #9 -11 using the following key word bank. a. Obligate anaerobes b. Obligate aerobes

Explanation / Answer

6. The purpose of phenol red in fermentation tube is to act as a pH indicator. So (c)

7. A positive test is indicated when the tube is yellow and bubbles are present in the Durham tube. So (a)

8. Durham tube are used for detection of gas bubbles. Gas production indicate utilisation of glucose by E.coli. So (b)

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