Question

Question 1: After recording the results from physiological testing, you will properly dispose of the plates in the biohazardous waste bag.

a) True

b) False

c) No answer text provided.

Question 2: If a Gram-positive coccus is catalase positive and presumed to be a staphylococcus, which of the following tests will be performed next?

a) Glucose fermentation test

b) coagulase test

c) antibiotic susceptibility test

d) Motility test

Question 3: If a Gram-positive coccus is catalase negative and thought to be a streptococcus, which of the following tests will be performed next?

a) blood agar test

b) coagulase test

c) antibiotic susceptibility test

d) motility test

Question 4: If nitrate is present in the media, then it will react with nitrate I and nitrate II to form a red compound. This is a positive result.

a) True b)False

Question 5:If no red color forms upon addition of nitrate I and II, this indicates which of the following:

a) The nitrate has not been converted to nitrite, a negative result.

b) Nitrate was converted to nitrite then immediately reduced to some other, undetectable form of nitrogen, a positive result.

c) Nitrate was converted to nitrite then immediately reduced to some other, undetectable form of nitrogen, a negative result.

d) Both a and b.

e) Both a and c.

Answer 1

Q1. Yes. The infectious organisms growing in the petri dishes must be properly discarded in biohazard bags so that they do not cause any disease outbreaks.

Q2.Answer is option B. Coagulase test.

Staphylococci can be differentiated from Streptococci with the help of Catalase test. Staphylococci are catalase positive.

Staphylococci can be further classified into Coagulase positive and coagulase negative staphylococci with the help of Coagulase test. Staphylococcus aureus is Coagulase positive.

Q3. Answer is option A. Blood Agar test.

Streptococci can be further identified with the help of the hemolysis pattern on blood agar media. Streptococcus pyogenes show complete hemolysis (beta hemolysis), Group D Streptococci show partial hemolysis (gamma hemolysis)

Q4. True.

nitrate reduction test is based on the detection of nitrite and its ability to form a red compound when it reacts with sulfanilic acid to form a complex (nitrite-sulfanilic acid) which then reacts with a α-naphthylamine to give a red precipitate (prontosil), which is a water-soluble azo dye.

Q5. Answer is option D) Both a and b.

When undetectable form of nitrogen is formed after addition of both reagents 1 and 2, adding Zinc powder helps whether the bacteria has reduced nittrate or not. No color formation indicates a positive test.