Sterilisation Culture Media & Pure Culture Techniques MCQs BSc Set-1

Clinical Microbiology

1. The medium used in membrane filter technique was 

(a). EMB agar 
(b). EMR-Vp medium 
(c). Lactose broth 
(d). Endo agar 

Answer:(b). EMR-Vp medium

2. Lysol is 

(a). Sterilant 
(b). Disinfectant 
(c). Antiseptic 
(d). Antifungal agent 

Answer:(b). Disinfectant

3. Which of the following is a neutral stain? 

(a). Picric acid 
(b). Giemsa 
(c). Neutral red 
(d). Malachite green 

Answer:(c). Neutral red

4. Peptone water medium is an example for 

(a). Synthetic medium 
(b). Semisynthetic medium 
(c). Differential medium 
(d). None of these 

Answer:(b). Semisynthetic medium

5. The method in which the cells are frozen dehydrated is called 

(a). Pasteurization 
(b). Desiccation 
(c). Disinfection 
(d). Lyophilization 

Answer:(d). Lyophilization

6. The technique used to avoid all microorganisms is accomplished by 

(a). Sterilization 
(b). Disinfection 
(c). Surgical sterilization 
(d). Disinfection Sterilization  

Answer:(a). Sterilization

7. Thermal death time is 

(a). Time required to kill all cells at a given temperature 
(b). Temperature that kills all cells in a given time 
(c). Time and temperature needed to kill all cells 
(d). All of the above 

Answer:(b). Temperature that kills all cells in a given time

8. A culture medium the exact composition of which is not known was called as 

(a). Simple 
(b). Complex 
(c). Defined
(d). Natural

Answer:(a). Simple

9. Elek’s gel diffusion test is used for the detection of 

(a). Tetani toxin 
(b). Cholera toxin 
(c). Diphtheria toxin 
(d). Toxoid 

Answer:(c). Diphtheria toxin

10. Temperature required for pasteurization is 

(a). Above 150oC 
(b). Below 100oC 
(c). 110oC 
(d). None of these 

Answer:(b). Below 100oC 

11. Separation of a single bacterial colony is called 

(a). Isolation 
(b). Separation 
(c). Pure culturing 
(d). All of these 

Answer:(a). Isolation

12. Which of the following is ion iz ing radiation? 

(a). U.V. rays 
(b). IR 
(c). γ-rays 
(d). None of these 

Answer:(c). γ-rays

13. Which of the following induces dimerisation of thymine? 

(a). X-rays 
(b). U.V. rays 
(c). a-rays 
(d). None of these 

Answer:(b). U.V. rays

14. When food materials are preserved at a temperature just above freezing temperature, the process is called. 

(a). Freezing 
(b). Pasteurisation 
(c). Chilling 
(d). Frosting 

Answer:(c). Chilling

15. Which of the following methods of sterilization has no effect on spores? 

(a). Drying 
(b). Hot air oven 
(c). Autoclave 
(d). None of these 

Answer:(a). Drying 

16. Treponema pallidum can be best identified using 

(a). Fluorescence microscope 
(b). Bright field microscope 
(c). Dark field microscope 
(d). Fluorescence microscope 

Answer:(b). Bright field microscope

17. Autoclaving is carried at 

(a). Dry heat 
(b). Atmospheric pressure 
(c). 120oC 
(d). All of these 

Answer:(c). 120oC 

18. Temperature in pasteurization is 

(a). 62.8o C 
(b). 35.7o C 
(c). 68.2oC 
(d). 60.8o C 

Answer:(a). 62.8o C

19. The bacterial culture prepared by pure culture method is 

(a). Inoculum 
(b). Suspension 
(c). Dilution 
(d). None of these 

Answer:(a). Inoculum

20. Algae are rich in 

(a). Carbohydrates 
(b). Proteins 
(c). Vitamins 
(d). All of these 

Answer:(d). All of these

21. L-Lysine is produced from 

(a). Corynebacterium glutamicum
(b). Clostridium botulinum 
(c). Mycobacterium sps 
(d). Pseudomonas 

Answer:(a). Corynebacterium glutamicum

22. The orderly increase in the quantity of all of the cellular components is known as 

(a). Reproduction 
(b). Growth 
(c). Binary fission 
(d). None of these 

Answer:(b). Growth

23. Theobacillus thio oxidans grow at pH 

(a). 7.0 
(b). 1.0 
(c). 6.0 
(d). 9.5 

Answer:(b). 1.0 

24. Slow freezing requires the conditions 

(a). 0o C to 15o C for 15 min. 
(b). – 6 o C to – 10o C for 10 min. 
(c). – 15o C to 3 to 72 hrs. 
(d). None of these 

Answer:(c). – 15o C to 3 to 72 hrs.

25. Discontinuous heating is called 

(a). Pasteurization 
(b). Sterilization 
(c). Fermentation 
(d). Tyndallization 

Answer:(d). Tyndallization

26. Isolation is 

(a). Purification of culture 
(b). Introduction of inoculum 
(c). Separation of a single colony 
(d). To grow microorganisms on surfaces

Answer:(c). Separation of a single colony

27. The condition required for autoclave 

(a). 121o C temp.and 15 lbs. pressure for 20 min. 
(b). 120o C temp.and 20 lbs. pressure for 30 min 
(c). 150o C temp.for 1 hr. 
(d). 130o C temp for 2 hr. 

Answer:(c). 150o C temp.for 1 hr.

28. Lysozyme is effective against

(a). Gram negative bacteria 
(b). Gram positive bacteria 
(c). Protozoa 
(d). Helminthes 

Answer:(b). Gram positive bacteria

29. Blood agar medium is 

(a). Enrichment medium 
(b). Enriched medium 
(c). Selective medium 
(d). Differential medium 

Answer:(b). Enriched medium 

30. Infrared radiation is a method of sterilization by 

(a). Dry heat 
(b). Moist heat 
(c). Chemical method 
(d). Mechanical method 

Answer:(d). Mechanical method 

31. Lyophilization means 

(a). Sterilization 
(b). Freeze-drying 
(c). Burning to ashes 
(d). Exposure to formation 

Answer:(b). Freeze-drying

32. Temperature used for 

(a) hot air oven is a. 100o C for 1 hour 
(b). 120o C for 1 hour 
(c). 160o C for 1 hour 
(d). 60oC for 1 hour 

Answer:(c). 160o C for 1 hour 

33. Phenol co-efficient indicates 

(a). Efficiency of a disinfectant 
(b). Dilution of a disinfectant
(c). Purity of a disinfectant 
(d). Quantity of a disinfectant 

Answer:(a). Efficiency of a disinfectant 

34. This is an agar plate method and is commonly used for estimation of the number of bacteria in milk. 

(a). Standard Plate Count (SPC) 
(b). Spread plate 
(c). Lawn culture 
(d). Roll tube method 

Answer:(a). Standard Plate Count (SPC) 

35. Agar is obtained from 

(a). Brown algae 
(b). Red algae 
(c). Green algae 
(d). Blue-green algae 

Answer:(b). Red algae

36. A gram positive organism which produces swarming on culture medium is 

(a). Salmonella 
(b). Clostridium 
(c). Staphylococci 
(d). Proteus 

Answer:(d). Proteus

37. Enhancement of virulence in bacteria is known as 

(a). Pathogenicity 
(b). Attenuation 
(c). Exaltation 
(d). Toxigenicity 

Answer:(c). Exaltation

38. For effective sterilization in an autoclave the temperature obtained is 

(a). 50o C 
(b). 100o C 
(c). 120oC 
(d). 180o C 

Answer:(c). 120oC

39. Spores are killed by 

(a). 70% alcohol 
(b). Glutaraldehyde 
(c). Autoclaving 
(d). Both b and c 

Answer:(d). Both b and c 

40. Glassware is sterilized by 

(a). Autoclaving 
(b). Hot air oven 
(c). Incineration 
(d). None of these 

Answer:(b). Hot air oven

41. Tyndallization was proposed by 

(a). Tyndall 
(b). Pasteur 
(c). Koch 
(d). Jenner 

Answer:(a). Tyndall

42. Viruses can be cultivated in 

(a). Lab media 

(b). Broth 
(c). Living cells 
(d). None of these 

Answer:(c). Living cells

43. By pasteurization 

(a). All the microorganisms can be removed 
(b). Only pathogenic forms can be removed 
(c). Only non-pathogenic forms can be removed 
(d). All of these are correct 

Answer:(b). Only pathogenic forms can be removed

44. The temperature required for pasteurization is 

(a). Above 100oC 
(b). Below 100oC 
(c). 100oC 
(d). None of these 

Answer:(b). Below 100oC 

45. In the medium other than nutrients, if any substance is used in excess, that medium is 

(a). Enriched medium 
(b). Special medium 
(c). Enrichment medium 
(d). None of these 

Answer:(a). Enriched medium

46. Example for indicator medium is 

(a). Nutrient Agar 
(b). Nutrient broth 
(c). Wilson and Blair 
(d). Czapek-dox medium 

Answer:(c). Wilson and Blair

47. Example of Anaerobic medium is 

(a). Robertson cooked-meat medium
(b). Nutrient agar 
(c). Nutrient broth 
(d). Mac-Conkey’s agar 

Answer:(a). Robertson cooked-meat medium

48. The differentiate lactose and non-lactose fermenters, the medium used is 

(a). Wilson & lair 
(b). Blood Agar 
(c). Tetrathionate broth 
(d). Mac-Conkey’s Agar

Answer:(d). Mac-Conkey’s Agar

49. Best method for getting pure culture is 

(a). Streak-plate 
(b). Agar slant 
(c). Both a & b 
(d). None of these 

Answer:(c). Both a & b 

50. To transfer cultures from one place to another, the device used is 

(a). Slant 
(b). Needle 
(c). Inoculation loop 
(d). Autoclave

Answer:(b). Needle