CELL CULTURES and CHARACTERISTICS Questions and Answers pdf :-

1. Which of the following bacteria can grow in acidic pH?

A. Vibrio cholerae
B. Lactobacilli
C. Shigella
D. Salmonella

Answer: B

2. Cell size and cell number can be measured using

A. hemocytometer
B. coulter counter
C. petroff-hausser counting chamber
D. none of these

Answer: B

3. Which of the following is used for the proper maintenance and preservation of pure cultures?

A. Periodic transfer to fresh media
B. Preservation by overlaying cultures with mineral oil
C. Preservation by lyophilization
D. All of the above

Answer: D

4. In the process of freeze drying, a dense cell suspension is placed in small vials and is frozen at

A. -60 to -78°C
B. -20 to -30°C
C. -30 to -48°C
D. -48 to -58°C

Answer: A

5. The solidifying agent commonly used in preparation of media is/are

A. agar
B. silica gel
C. both (a) and (b)
D. none of these

Answer: C

6. Which of the following chemotherapeutic agents may affect the growth of Campylobacter jejuni?

A. Vacomycin
B. Polymyxin
C. Trimethoprim
D. None of these

Answer: D

7. To select cholera-causing bacterium, Vibrio cholerae, the pH of the medium is maintained at a pH of

A. 8.5
B. 8.90
C. 6.79
D. 3.5

Answer: A

8. For the selection of endospore-forming bacteria, a mixed culture can be heated at

A. 80°C for 10 minutes
B. 70°C for 10 minutes
C. 60°C for 10 minutes
D. 90°C for 10 minutes

Answer: A

9. The concentration of agar to obtain semi solid media is

A. 1.5-20%
B. 0.5% or less
C. >10%
D. >10%but<20%

Answer: B

10. Which of the following bacteria dies quickly after drying?

A. Treponema pallidium
B. Mycobacterium tuberculosis
C. Staphylococcus aureus
D. Pseudomonas aeruginosa

Answer: A

11. Mac-Conkey medium is an example of

A. transport medium
B. enrichment medium
C. differential medium
D. all of these

Answer: C

12. Pseudomonas aeruginosa forms a blue water soluble pigment called

A. pyocyanin B. chlororaphin
C. pyoverdin D. β-carotene

Answer: A

13. Agar is used for solidifying culture media because

A. it does not affect by the growth of bacteria
B. it does not add to the nutritive properties of the medium
C. the melting and solidifying points of agar solution are not the same
D. all of the above

Answer: D

14. For the selection of lactobacilli present in cheddar cheese, the pH of the medium is maintained at

A. 6.35 B. 5.35
C. 4.35 D. 5.75

Answer: B

15. A disease producing species occurring in a mixed culture can often be selected on the basis of its

A. pathogenic properties
B. special carbon source
C. special nitrogen source
D. none of these

Answer: A

16. Important example(s) of enriched medium/media is/ are

A. Loeffler’s serum slope
B. Bordet-gengou medium
C. Blood agar
D. All of these

Answer: D

17. Cell counting can be carried out by

A. direct microscopic count using petroffhansser counting chamber
B. plate counting
C. membrane filter count
D. all of the above

Answer: D

18. Which of the following techniques may be performed quantitatively to determine the number of bacteria of a particular type?

A. Pour plate
B. Spread plate
C. Both (a) and (b)
D. Streak plate technique

Answer: C

19. Intestinal bacteria can grow in the presence of __________ whereas nonintestinal bacteria are usually inhibited.

A. bile salts
B. low concentration of various dyes
C. sugars
D. low levels of nitrogen

Answer: A

20. Which of the following problem makes it impossible to satisfy all of Koch’s postulates?

A. Microorganism causes serious symptoms in humans
B. Microorganism cannot be isolated in pure culture
C. Species of microorganism is in question
D. Genes from the microorganism cannot be amplified by PCR

Answer: B

CELL CULTURES and CHARACTERISTICS Questions and Answers pdf ::

21. A medium containing crystal violet dye plus sodium deoxycholate will allow

A. gram (-)ve intestinal bacteria to grow
B. gram (+)ve intestinal bacteria to grow
C. aquatic bacteria to grow
D. none of these

Answer: A

22. Which of the following bacteria can grow in alkaline pH?

A. Shigella
B. Lactobacilli
C. Salmonella
D. Vibrio cholerae

Answer: D

23. All bacteria that inhabit the human body are

A. heterotrophs B. chemolithotrophs
C. autotrophs D. phototroph

Answer: A

24. When a substance is added to a liquid medium which inhibits the growth of unwanted bacteria and favors the growth of wanted bacteria, it is known as

A. differential medium
B. enriched medium
C. enrichment medium
D. selective medium

Answer: C

25. Which of the following methods is most likely to be quantitative?

A. Dilution and plating
B. Gram staining
C. Wet mount
D. None of these

Answer: A

26. Which of the following hint(s) suggest/s that a given specimen is likely to contain anaerobic bacteria?

A. Gas in specimen
B. Foul odour
C. Presence of sulphur granules
D. All of these

Answer: D

27. Viable plate count can be obtained using

A. Spread plate method
B. Pour plate method
C. both (a) and (b)
D. Hemocytometer

Answer: C

28. In the pour plate method, the mixed culture is diluted directly in tubes of

A. liquid agar medium
B. sterile liquid usually water
C. both (a) and (b)
D. none of these

Answer: A

29. Treponema species from human oral cavity can be selected by using

A. pH of the medium
B. incubation temperature
C. cell size and motility
D. all of these

Answer: C

30. When a substance is added to a solid medium which inhibits the growth of unwanted bacteria but permits the growth of wanted bacteria, it is known as

A. differential medium
B. enriched medium
C. enrichment medium
D. selective medium

Answer: D

31. Peptone water and nutrient broth are

A. selective media
B. enriched media
C. basal media
D. none of these

Answer: C

32. Stuart’s transport medium is used for transport of specimen containing

A. Neisseria gonorrhoeae
B. Salmonella
C. Vibrio cholerae
D. Shigella

Answer: A

33. Plate counts are often reported as

A. cfu
B. cfu/ml
C. Both (a) and (b)
D. thousands/ml

Answer: B

34. The medium which allows the growth of more than one microorganisms of interest but with morphologically distinguishable colonies is known as

A. selective medium
B. enrichment medium
C. differential medium
D. none of these

Answer: C

35. Selective media facilitate growth of only one kind of organism. Saboraud medium is used to selectively isolate

A. coliform bacteria
B. gram positive bacteria
C. yeasts
D. acid fast organisms

Answer: C

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