2025-2026 SERIES
MICROBIOLOGY LAB - EXAM 2 COMPLETE
QUESTIONS AND CORRECT ANSWERS | GRADED
AND THE LATEST SERIES
medium
Ans: a mixture of nutritional substances on or in which microorganisms grow
Question: autotroph
Ans: nutritionally deficient mutants that have lost the ability to synthesize a
particular enzyme
many microorganisms in this group:
- can carry out photosynthesis
- usually do not cause disease
- synthesize organic compounds to obtain energy
Question: heterotroph
Ans: an organism that uses compounds to produce biomolecules
Question: autoclave
Ans: an instrument for sterilization by means of moist heat under pressure
Question: Autoclaving combines ____ and ____ to destroy high resistant
bacteria.
, 2025-2026 SERIES
Ans: high temp and high pressure
Question: What are six basic nutritional requirements of every living thing?
Ans: Water, carbon, nitrogen, metallic elements, energy and growth factors such
as vitamins
Question: general purpose media
Ans: Designed to grow a broad spectrum of microbes that do not have special
growth requirements
Question: enriched media
Ans: medium that contains special additives that could promote certain metabolic
activities. (ex. trypticase soy agar, blood agar, yeast extract broth)
- especially used for fastidious bacteria
Question: selective media
Ans: is a nutrient that inhibits the growth of a certain type of microorganisms (ex.
Gram + bacteria) while permitting the growth of a different type (in this example,
Gram - )
Question: differential media
Ans: medium which will differentiate between bacteria based on how they
change the medium or their appearance on the medium
Question: EMB and HE are both ____ and ____.
, 2025-2026 SERIES
Ans: selective and differential
Question: EMB and HE are selective for ____ and differential for ____.
Ans: selective for gram-negative bacteria and differential for lactose fermenters.
Question: What do lactose fermenters and nonfermenters look like on each
media?
Ans: - Organisms which quickly ferment lactose will give dark-green to black
colonies on this medium; these colonies have a metallic sheen (Ecoli)
- Organisms that are slow fermenters of lactose will give pink to maroon colonies on
this medium. Those organisms that cannot ferment lactose at all give white
(colorless) colonies on EMB agar (since nonfermenters of lactose are often high
pathogenic, this is a useful way to identify potential pathogens)
Question: What is Shigella associated with?
Ans: a genus associated with bacillary dysentery
Question: HE and EMB are useful for distinguishing between _____.
Ans: Enterobacteriaceae
Question: What are Enterobacteriaceae?
Ans: a group of short, Gram-negative, facultative anaerobic rods that are found
in the intestinal tract of various mammals, including humans
Question: PEA and MS agar are _____ for ____.
MICROBIOLOGY LAB - EXAM 2 COMPLETE
QUESTIONS AND CORRECT ANSWERS | GRADED
AND THE LATEST SERIES
medium
Ans: a mixture of nutritional substances on or in which microorganisms grow
Question: autotroph
Ans: nutritionally deficient mutants that have lost the ability to synthesize a
particular enzyme
many microorganisms in this group:
- can carry out photosynthesis
- usually do not cause disease
- synthesize organic compounds to obtain energy
Question: heterotroph
Ans: an organism that uses compounds to produce biomolecules
Question: autoclave
Ans: an instrument for sterilization by means of moist heat under pressure
Question: Autoclaving combines ____ and ____ to destroy high resistant
bacteria.
, 2025-2026 SERIES
Ans: high temp and high pressure
Question: What are six basic nutritional requirements of every living thing?
Ans: Water, carbon, nitrogen, metallic elements, energy and growth factors such
as vitamins
Question: general purpose media
Ans: Designed to grow a broad spectrum of microbes that do not have special
growth requirements
Question: enriched media
Ans: medium that contains special additives that could promote certain metabolic
activities. (ex. trypticase soy agar, blood agar, yeast extract broth)
- especially used for fastidious bacteria
Question: selective media
Ans: is a nutrient that inhibits the growth of a certain type of microorganisms (ex.
Gram + bacteria) while permitting the growth of a different type (in this example,
Gram - )
Question: differential media
Ans: medium which will differentiate between bacteria based on how they
change the medium or their appearance on the medium
Question: EMB and HE are both ____ and ____.
, 2025-2026 SERIES
Ans: selective and differential
Question: EMB and HE are selective for ____ and differential for ____.
Ans: selective for gram-negative bacteria and differential for lactose fermenters.
Question: What do lactose fermenters and nonfermenters look like on each
media?
Ans: - Organisms which quickly ferment lactose will give dark-green to black
colonies on this medium; these colonies have a metallic sheen (Ecoli)
- Organisms that are slow fermenters of lactose will give pink to maroon colonies on
this medium. Those organisms that cannot ferment lactose at all give white
(colorless) colonies on EMB agar (since nonfermenters of lactose are often high
pathogenic, this is a useful way to identify potential pathogens)
Question: What is Shigella associated with?
Ans: a genus associated with bacillary dysentery
Question: HE and EMB are useful for distinguishing between _____.
Ans: Enterobacteriaceae
Question: What are Enterobacteriaceae?
Ans: a group of short, Gram-negative, facultative anaerobic rods that are found
in the intestinal tract of various mammals, including humans
Question: PEA and MS agar are _____ for ____.
