True or False: Growth media is best suited for distinguishing between two similar species of
bacteria - ANSWER False. Growth media is designed to simply support (and not restrict)
microbial growth
What are the requirements of a fastidious microbe? (short answer) - ANSWER A fastidi-
ous microbe is an organism with complex growth requirements such that is absent it will not
grow. Enriched medias thus contain these specific and essential nutrients required for the
growth of a particular subset of microorganisms.
True or False: LB agar is classified as a selective, non-differential media - ANSWER False
What is agar used for in microbiology? (short answer) - ANSWER Agar is used to create a
solid, smooth surface on which microbes can grow
Alpha hemolysis (matching) - ANSWER Incomplete hemolytic activity
Beta hemolysis (matching) - ANSWER Complete hemolytic activity
Gamma hemolysis (matching) - ANSWER No hemolytic activity
Columbia CNA agar is most closely related to which media (multiple choice) - ANSWER
CNA agar is similar to VAP as it is also enriched with blood and allows for differentiation
based on hemolytic patterns
1
, True or False: Chocolate agar gets its brown color from cocoa to produce an enriched media
- ANSWER False
In an attempt to detect the presence of the pathogenic strain of e coli O157:H7, a researcher
spread culture onto a MacConkey agar with failed results. What type of agar should they
(correctly) try next? Why? (short answer) - ANSWER The microbe should be plated on
SMAC as it is specifically formulated to detect O157:H7. Pathogenic e coli cannot ferment
sorbitol while non-pathogenic e coli can ferment both sorbitol and lactose. Therefore, colo-
nies that ferment can be differentiated from non-fermenters.
What is the gram status of microbes growing on eosin methylene blue agar plates? (short
answer) - ANSWER Gram-negative
What is the process of spreading a bacterial culture onto a petri dish? (short answer) - AN-
SWER Plating
Mannitol salt agar will turn what color in the presence of the pathogenic strain staphylococ-
cus aureus? (short answer) - ANSWER Yellow
In order to visual individual colonies of bacteria, would you culture your sample in a liquid
media or on a solid (agar) media? Why? (short answer) - ANSWER Solid media. The pri-
mary advantage is that cells are held into place. When grown in a nutrient broth, bacterial
cells can multiply but are free to move around in solution. When grown on agar within a pe-
tri dish the fixed in such a way as to form colonies
True or False: the visualization of colonies on a petri dish represents bacterial cells that have
often multiplied a million times over - ANSWER True
True or False: the purpose of a quadrant streak expand a bacterial population - ANSWER
False
2
bacteria - ANSWER False. Growth media is designed to simply support (and not restrict)
microbial growth
What are the requirements of a fastidious microbe? (short answer) - ANSWER A fastidi-
ous microbe is an organism with complex growth requirements such that is absent it will not
grow. Enriched medias thus contain these specific and essential nutrients required for the
growth of a particular subset of microorganisms.
True or False: LB agar is classified as a selective, non-differential media - ANSWER False
What is agar used for in microbiology? (short answer) - ANSWER Agar is used to create a
solid, smooth surface on which microbes can grow
Alpha hemolysis (matching) - ANSWER Incomplete hemolytic activity
Beta hemolysis (matching) - ANSWER Complete hemolytic activity
Gamma hemolysis (matching) - ANSWER No hemolytic activity
Columbia CNA agar is most closely related to which media (multiple choice) - ANSWER
CNA agar is similar to VAP as it is also enriched with blood and allows for differentiation
based on hemolytic patterns
1
, True or False: Chocolate agar gets its brown color from cocoa to produce an enriched media
- ANSWER False
In an attempt to detect the presence of the pathogenic strain of e coli O157:H7, a researcher
spread culture onto a MacConkey agar with failed results. What type of agar should they
(correctly) try next? Why? (short answer) - ANSWER The microbe should be plated on
SMAC as it is specifically formulated to detect O157:H7. Pathogenic e coli cannot ferment
sorbitol while non-pathogenic e coli can ferment both sorbitol and lactose. Therefore, colo-
nies that ferment can be differentiated from non-fermenters.
What is the gram status of microbes growing on eosin methylene blue agar plates? (short
answer) - ANSWER Gram-negative
What is the process of spreading a bacterial culture onto a petri dish? (short answer) - AN-
SWER Plating
Mannitol salt agar will turn what color in the presence of the pathogenic strain staphylococ-
cus aureus? (short answer) - ANSWER Yellow
In order to visual individual colonies of bacteria, would you culture your sample in a liquid
media or on a solid (agar) media? Why? (short answer) - ANSWER Solid media. The pri-
mary advantage is that cells are held into place. When grown in a nutrient broth, bacterial
cells can multiply but are free to move around in solution. When grown on agar within a pe-
tri dish the fixed in such a way as to form colonies
True or False: the visualization of colonies on a petri dish represents bacterial cells that have
often multiplied a million times over - ANSWER True
True or False: the purpose of a quadrant streak expand a bacterial population - ANSWER
False
2
