E-PolyLearning

21. Which of the following method can be used to determine the number of bacteria quantitatively?
a. Streak-plate
b. Spread-plate
c. Pour plate
d. Pour-plate and spread plate
View Answer Report Discuss 50-50!
Answer: (d).Pour-plate and spread plate

22. Dilution of the mixed culture is a common step in all the three methods: the streak-plate,the spread-plate and the pour-plate technique.
a. True
b. False
c. May be
d. Can't say
View Answer Report Discuss 50-50!
Answer: (b).False

23. Which of the following are not performed in lyophilization?
a. agar slant is covered with mineral oil
b. cell suspension is frozen at -60 degree to -78 degree C
c. vials are connected to high-vacuum line
d. bacterial sample is dehydrated
View Answer Report Discuss 50-50!
Answer: (a).agar slant is covered with mineral oil

24. Which of the following is a function of cryoprotective agents?
a. for long-term preservation of cultures
b. prevents cell damage due to ice crystal formation
c. prevents formation of ice
d. to trap the liquid nitrogen
View Answer Report Discuss 50-50!
Answer: (b).prevents cell damage due to ice crystal formation

25. What is the temperature of liquid nitrogen?
a. -120 degree C
b. 0 degree C
c. -150 degree C
d. -196 degree C
View Answer Report Discuss 50-50!
Answer: (d).-196 degree C

Page 5 of 21