BIO 171 Module 4 Exam
1. True or False: Differential media is best suited for distinguishing between two similar species ofbacteria.
True. Growth media does not contain restrictive factors, while selective media is best used toencourage
the growth of one microbe while simultaneously discouraging the growth of the other. Since two similar
species of microbes are being studied they must be differentiated under similar but just slightly different
conditions (differential media).
2. A researcher is asked to determine if a sample contains Neisseria meningitides. Knowing Neisseria
meningitides is slow growing and other foreign microbes may also be present in theculture, which type
of media would be best suited:
A. Growth media
B. Differential media
C. Selective media
D. Selective and Differential media
C. Selective media. If additional foreign microbes may be present in your sample and you know Neisseria
meningitides is slow growing, you must restrict the unwanted microbes whilesupporting the growth of
Neisseria meningitides. Thus, you are selectively encouraging one microbes growth, while selectively
restricting others.
1. True or False: LB agar is classified as a selective, non-differential media.
False. LB agar is the most basic type of agar and like LB media supports the growth ofvirtually all
microbes without restriction.
2. What is agar used for in microbiology?
, Agar is used to create a solid, smooth surface on which microbes can grow.
1. Match the following hemolytic class with its description of activity.
1. Alpha hemolysis A. No hemolytic activity
B
2. Beta hemolysis B. Incomplete hemolytic
C activity
3. Gamma hemolysis C. Complete hemolytic activity
A
1. True or False: Differential media is best suited for distinguishing between two similar species ofbacteria.
True. Growth media does not contain restrictive factors, while selective media is best used toencourage
the growth of one microbe while simultaneously discouraging the growth of the other. Since two similar
species of microbes are being studied they must be differentiated under similar but just slightly different
conditions (differential media).
2. A researcher is asked to determine if a sample contains Neisseria meningitides. Knowing Neisseria
meningitides is slow growing and other foreign microbes may also be present in theculture, which type
of media would be best suited:
A. Growth media
B. Differential media
C. Selective media
D. Selective and Differential media
C. Selective media. If additional foreign microbes may be present in your sample and you know Neisseria
meningitides is slow growing, you must restrict the unwanted microbes whilesupporting the growth of
Neisseria meningitides. Thus, you are selectively encouraging one microbes growth, while selectively
restricting others.
1. True or False: LB agar is classified as a selective, non-differential media.
False. LB agar is the most basic type of agar and like LB media supports the growth ofvirtually all
microbes without restriction.
2. What is agar used for in microbiology?
, Agar is used to create a solid, smooth surface on which microbes can grow.
1. Match the following hemolytic class with its description of activity.
1. Alpha hemolysis A. No hemolytic activity
B
2. Beta hemolysis B. Incomplete hemolytic
C activity
3. Gamma hemolysis C. Complete hemolytic activity
A
