Bacterial Growth
All bacteria have optimal growth requirements which include such things as: temperature,
pH, humidity, salinity, etc. If anyone of these growth requirements are not met, the bacterial cultures
will not survive.
Define:
Aerobic:
requiring oxygen
Anaerobic:
not requiring oxygen
`philos':
loving
`phobia':
hating
Term
Thermophile
Psychrophile
Mesophile
or
Acidophile
Alkalophile
Halophile
Heterotrophic
Autotrophic
Nitrogen
fixing
bacteria
Microflora
Definition
Bacterial Example
heat loving bacterium
(very hot environment)
cold-loving bacteria
(12-15 degrees C)
environments of
pH < 7
(acidic)
environments of pH > 7
(necessary for survival basic)
bacteria that grows well in salty
conditions
(high osmotic pressure)
bacteria that obtains its nutrients by
eating organic material
Use CO2 as their sole source of Carbon
(CO2 ──6 organic Carbon)
bacteria that are able to take nitrogen
(N2) from the air and `fix' it into
ammonia
the microbial life found within a
particular environment (i.e. - the
microflora of our bodies, soil, etc...)
Clostridium,
Streptococcus spp.
Pseudomonas,
Blavobacterium spp.
Thiobacilli
Bacillus spp.
Halobacterium spp.
Escherecheri
coli
Cyanobacteria
Azotobacteria spp. in soil,
Rhizobium in root nodules
Bacteria inside the human
body (intestine, mouth,
urogenital tract).
Label the following chart, place the terms in their correct position and describe each term.
Growth Curve
10.0
9.0
log10
8.0
viable
7.0
Viable
count
6.0
5.0
Time
lag phase:
bacteria adapt themselves to their new environment
growth phase: bacteria count increases in a linear fashion
stationary phase: growth of bacteria slows down due to various changes [oxygen, pH]
death phase: culture starts to die off - waste products build up and nutrients become scarce
doubling time: time it takes for the population to double in number. This is a characteristic of a
given bacterial strain when it is grown in a standardmedium