October 2022

Q. Which of the following bacteria dies quickly after drying? Treponema pallidium Mycobacterium tuberculosis Staphylococcus aureus Pseudomonas aeruginosa Answer: Treponema pallidium

Q. The concentration of agar to obtain semi solid media is 1.5-20% 0.5% or less >10% >10%but<20% Answer: 0.5% or less

8. For the selection of endospore-forming bacteria, a mixed culture can be heated at 80°C for 10 minutes 70°C for 10 minutes 60°C for 10 minutes 90°C for 10 minutes Answer: 80°C for 10 minutes

Q. To select cholera-causing bacterium, Vibrio cholerae, the pH of the medium is maintained at a pH of 8.5 8.90 6.79 3.5 Answer: 8.5

Q. Which of the following chemotherapeutic agents may affect the growth of Campylobacter jejuni? Vacomycin Polymyxin Trimethoprim None of these Answer: None of these

Q. The solidifying agent commonly used in preparation of media is/are agar silica gel both (1) and (2) none of these Answer: both (1) and (2)

Q. In the process of freeze drying, a dense cell suspension is placed in small vials and is frozen at -60 to -78°C -20 to -30°C -30 to -48°C -48 to -58°C Answer: -60 to -78°C

Q. Which of the following is used for the proper maintenance and preservation of pure cultures? Periodic transfer to fresh media Preservation by overlaying cultures with mineral oil Preservation by lyophilization All of the above Answer: All of the above