Question

86.   Which one of the following statements about carbohydrate fermentation tests is false?                                

A. The carbohydrate fermentation broths contain the pH indicator phenol red.                                         

B. Bacteria that grow by fermenting a sugar usually excrete some acidic waste product                                       

C. If the bacterium cannot use the sugar in the carbohydrate fermentation broth, they can’t grow in that medium                                                                                                                                                                  

D. The carbohydrate fermentation broths contain a Durham tube to detect gas production.                         

87. Which of the following is incorrect about stains?                                                                                        

A. Flagella stain is called the Common Ryu stain                                                                                               

B. Capsules are observed as halos around bacterial cells by negative staining                                                  

C. Basic dyes include india ink, crystal violet and safranin                                                                                   

D. Acid fast stain is called Ziehl-Neelsen stain   

88. 88. When compared to Kligler’s Iron Agar slant, Lysine Iron Agar slant is unique in that:    

A. It identifies whether a bacterium decarboxylates or deaminates lysine.                                                                                  

B. It uses bromocresol purple as a pH indicator.                                                                                                    

C. It contains 0.1% glucose and 1% lysine.                                                                                                            

D. It doesn’t detect gas production be it CO₂, H₂ or H₂S.                                                                                 

E. All of the above.                                                                                                                                                          

F. A, B, and C                                                                                                                                                           

G. A, B and D                                                                                                                                                                   

H. B, C and D

Answer 1

86.  Statements about carbohydrate fermentation tests-

A. The carbohydrate fermentation broths contain the pH indicator phenol red

This statement is true

B. Bacteria that grow by fermenting a sugar usually excrete some acidic waste product.

False- bacteria do not excrete acidic waste

C. If the bacterium cannot use the sugar in the carbohydrate fermentation broth, they can’t grow in that medium

True- Bacteria those are unable to process sugar will not get carbon which is essential for growth and eventually they will not grow in the medium

D.The carbohydrate fermentation broths contain a Durham tube to detect gas production.

This statement is true

So as for the question the correct option is - B

87. incorrect about stains-

A. Flagella stain is called the Common Ryu stain -True

B. Capsules are observed as halos around bacterial cells by negative staining - True

C. Basic dyes include india ink, crystal violet and safranin - False

(India ink is a negetive stain and not basic )

D. Acid fast stain is called Ziehl-Neelsen stain - true

(named afte two German doctors who modified the stain to identify acid fast organism)

So the incorrect option is- C

88. When compared to Kligler’s Iron Agar slant, Lysine Iron Agar slant is unique in that:

a. It identifies whether a bacterium decarboxylates or deaminates lysine : True

(Lysine iron agar (LIA) slants identifies bacteria based on the ability to deaminate or decarboxylate lysine)

b. It uses bromocresol purple as a pH indicator.- True.

(The pH indicator in LIA is bromocresol purple while in KIA is phenol red)

c. It contains 0.1% glucose and 1% lysine- True

(LIA contain lysin but KIA doesnot)

d. It doesn’t detect gas production be it CO2, H2 or H2S- False

(It can detect H2S production. This medium contain Ferric ammonium citrate as an indicator of H2S. It turns black upon H2S production)

So based on the statements the correct option is -

F. A, B and C