Microbiology Questions and Answers – Pure Cultures and Cultural Characteristics – Selective Methods

«
»

This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Pure Cultures and Cultural Characteristics – Selective Methods”.

1. Isolation of pure culture refers to ___________
a) purification of culture
b) introduction of inoculum
c) separation of a single colony
d) to grow microorganisms on a surface
View Answer

Answer: c
Explanation: To study the characteristics of one species, that species must be separated from all the other colonies of species, i.e., it must be isolated in pure culture.
advertisement

2. Enrichment media allows the growth of a large number of varied bacterial species.
a)True
b) False
View Answer

Answer: b
Explanation: Enrichment media is a selective method used for the enhancement of the growth of a particular bacterial species.

3. Which of the following is not a physical method for selection of pure culture?
a) Heat treatment
b) pH of the media
c) Cell size and motility
d) Use of dilute media
View Answer

Answer: d
Explanation: Use of dilute media is a chemical method of selection in which a mixed culture was inoculated into a very dilute medium to isolate a particular bacterial colony.

4. In physical method of selection, endospore-forming bacteria can be obtained by heating the mixed culture to _____________
a) 70 degree C for 10 minutes
b) 80 degree C for 10 minutes
c) 60 degree C for 10 minutes
d) 90 degree C for 10 minutes
View Answer

Answer: b
Explanation: To select for endospore-forming bacteria, a mixed culture can be heated to 80 degrees C for 10 minutes before being used to inoculate culture media. Vegetative cells will be killed by this treatment but endospores will survive and subsequently germinate and grow.
advertisement

5. Vibrio cholerae can grow in a medium with a pH of _______
a) 5.5
b) 7.0
c) 8.5
d) 2.0
View Answer

Answer: c
Explanation: Vibrio cholerae, cholera causing bacterium can be selected from a medium with a ph of 8.5; most intestinal bacteria are unable to grow at this pH.

6. Disease-producing species occurring in a mixed culture can be selected by taking advantage of _________
a) its pathogenic properties
b) special carbon source
c) special nitrogen source
d) toxic chemicals
View Answer

Answer: a
Explanation: In the biological method of selection, a disease producing species occurring in a mixed culture can often be selected by taking advantage of its pathogenic properties. Others are chemical methods of selection.

7. Treponema sp. can be selected by taking advantage of ____________
a) small cell size
b) motility
c) dilute media
d) small cell diameter and bacterial motility
View Answer

Answer: d
Explanation: Treponema sp. from the human oral cavity can be selected by taking advantage of its small diameter and bacterial motility. They have the ability to swim through solid agar media.
advertisement

8. A large cluster of colonies are obtained in streak plate method.
a) True
b) False
View Answer

Answer: b
Explanation: In streak plate method, the bacterial cells are thinned out so that the bacterial cells are far apart in the medium to ensure that colony developing from one cell does not merge with that growing from another.

Sanfoundry Global Education & Learning Series – Microbiology.

To practice all areas of Microbiology, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn