1|Page
GCSU (Bachoon) Microbiology Test 2
Actual Questions With Verified Solutions
chemically defined media - correct-answer -- exact chemical composition is
known.
complex media - correct-answer -- exact composition is not known
- made up of nutrients including extracts from yeasts, blood, meat, plants, or
digests proteins from these and other sources
What are complex media good for growing? - correct-answer -good for growing
heterotrophic bacteria
selective media - correct-answer -- suppresses the growth of unwanted bacteria
and encourages the growth of the desired microbe
- Ex. salt, dyes that inhibit Gm+
differential media - correct-answer -- makes it easier to distinguish colonies of
desired organisms
,2|Page
- Ex: blood agar plate, EMB, MAC, MSA
enrichment culture - correct-answer -- used to grow bacteria present in small
numbers
- ex: from soil - oil degraders
In what way do bacteria grow? - correct-answer -- an increase in numbers not an
increase in size
- reproduce by binary fission
- some reproduce by budding
- a few filamentous types reproduce by fragmentation
generation time - correct-answer -- (2^n) n = # of generations
- the time required for a cell to divide and it's population to double
Ex: E. coli = 20 min. other bacteria = 24 hrs or more
what is the usual bacteria generation time? - correct-answer -1 to 3 hours
, 3|Page
bacterial growth curve - correct-answer -
lag phase - correct-answer -- intense activity preparing for population growth but
no increase in population
- little or no cell division
- it can last for hours or days
- synthesizing lots of enzymes
log phase - correct-answer -- logarithmic or exponential increase in population
- reproduction is most active
- generation time reaches a constant minimum
- cells are sensitive to adverse conditions (radiation, antibiotics)
stationary phase - correct-answer -- period of equilibrium; microbial deaths
balances production of new cells
- metabolic activity slows due to exhaustion of nutrients (waste accumulation, pH
change, etc..)
death phase - correct-answer -- population is decreasing at a logarithmic rate
- death exceeds the number of new cells
GCSU (Bachoon) Microbiology Test 2
Actual Questions With Verified Solutions
chemically defined media - correct-answer -- exact chemical composition is
known.
complex media - correct-answer -- exact composition is not known
- made up of nutrients including extracts from yeasts, blood, meat, plants, or
digests proteins from these and other sources
What are complex media good for growing? - correct-answer -good for growing
heterotrophic bacteria
selective media - correct-answer -- suppresses the growth of unwanted bacteria
and encourages the growth of the desired microbe
- Ex. salt, dyes that inhibit Gm+
differential media - correct-answer -- makes it easier to distinguish colonies of
desired organisms
,2|Page
- Ex: blood agar plate, EMB, MAC, MSA
enrichment culture - correct-answer -- used to grow bacteria present in small
numbers
- ex: from soil - oil degraders
In what way do bacteria grow? - correct-answer -- an increase in numbers not an
increase in size
- reproduce by binary fission
- some reproduce by budding
- a few filamentous types reproduce by fragmentation
generation time - correct-answer -- (2^n) n = # of generations
- the time required for a cell to divide and it's population to double
Ex: E. coli = 20 min. other bacteria = 24 hrs or more
what is the usual bacteria generation time? - correct-answer -1 to 3 hours
, 3|Page
bacterial growth curve - correct-answer -
lag phase - correct-answer -- intense activity preparing for population growth but
no increase in population
- little or no cell division
- it can last for hours or days
- synthesizing lots of enzymes
log phase - correct-answer -- logarithmic or exponential increase in population
- reproduction is most active
- generation time reaches a constant minimum
- cells are sensitive to adverse conditions (radiation, antibiotics)
stationary phase - correct-answer -- period of equilibrium; microbial deaths
balances production of new cells
- metabolic activity slows due to exhaustion of nutrients (waste accumulation, pH
change, etc..)
death phase - correct-answer -- population is decreasing at a logarithmic rate
- death exceeds the number of new cells
