Ch.6 Microbial Growth Flashcards
what are the physical requirements for growth?
temp, pH, osmotic pressure
what is the optimal temp for psychrophiles ?
0 to 20-25 C
what is the optimal temp for mesophiles ?
37 C
what’s the optimal temp for thermophiles?
40 to 75-80 C
what is the optimal temp for hyperthermophiles?
> 80 C
what happens in a HYPERtonic solution?
water exits the cell
plasmolysis occurs(shrinkage of cytoplasm)
what happened in HYPOtonic solution?
water enters the cell
cell swells
what is the pH for acidophiles?
< 6
what is the pH for alkaliohiles?
> 8
what is the range of pH for molds & fungi?
range of 5-6
what are the chemical requirements for growth?
carbon
oxygen
nitrogen
hydrogen
phosphorus
sulfur
potassium
magnesium
calcium
iron
what is chonps?
carbon
hydrogen
oxygen
nitrogen
phosphorus
sulfur
what is life’s molecules mostly comprised of ?
CHONPS
DNA
RNA
Proteins
Lipids
Carbohydrates
what are essential nutrients?
nutrients that cannot be synthesized and must be supplied other waste growth ceases
what are the required micronutrients?
Co
Cu
Mn
Mo
Ni
Z
what are the organic growth factors?
vitamins
amino acids
blood
serum
what neutralizes the affect of O2 radicals?
Superoxide dimutase
where is SOD found?
found in aerobes, aerotolerant aerobes, facultative anaerobes
what does catalase and peroxidase do?
neutralize peroxide anion (O262-) found in H2O2
what are aerobes?
are aerobic respires that use O2
what can aerobes be?
obligate aerobe
Microaerophile
what is an anaerobe?
they do not use O2
they ferment or respire anaerobically
what can an anaerobe be?
obligate anaerobe (O2 is toxic)
Aerotolenant anaerobe(O2 is not toxic )
what is a facultative anaerobe
they can use or not use oxygen
they can ferment or respire aerobically or anaerobically
what forms growth medium?
both macro and micro nutrients
what is complex rich media?
it contain majority pre-formed nutrients cells that can readily assimilate
where does complex media get its nutrients?
protein source
Ex:
beef
casein
soy protein
what do yeast and beef extract help with?
vitamins and growth factors
what is defined media?
it is when the chemical composition is known
cells must sythesize all required molecules
when is defined media required?
fastidious bacteria
what the amount of peptone in the nutrient agar?
0.5%
what is the amount of beef extract in the nutrient agar?
0.3%
what’s the amount of NaCl in the nutrient agar ?
0.5%
what are the culture media types?
─ Liquid: & Solid:
what is liquid media types used for ?
for growth studies, biochemical analysis,
harvest cells for DNA, protein isolation
what is solid media used for ?
liquid media containing solidifying agent (agar);
formation of colonies
what employs components to inhibit certain bacterial type over others?
selective media
What allows for visualization of metabolic difference between types?
differential media
We are inside E. coli. If this E. coli were anaerobically respiring, which
location (1-5) would easily indicate/show this to us?
1. Location 1
2. Location 2
3. Location 3
4. Location 4
5. Location 5
Fermentation
A. generally relies on oxidative phosphorylation to supply ATPs.
B. is the same as anaerobic respiration.
C. utilizes an ATPase (ATP synthase).
D. requires oxygen.
E. includes reaction(s) that
re-supply NAD+.
F. Two of A - E are true.
Which statement is false?
A. Phototrophs that are anoxygenic do not use water as an electron source.
B. Oxygen is formed during oxygenic photosynthesis.
C. CO2 becomes reduced to glucose and other sugars during CO2 fixation in the Calvin cycle.
D. Photosystem II is linked to photophosphorylation.
E. All phototrophs possess both Photosystem I and Photosystem II.
What would the three bacterial types described below all have in common with respect to the given characteristics?
Type 1: a psychrophilic, alkalophilic, facultative anaerobe
Type 2: a thermophilic, halophilic, aerotolerant anaerobe
Type 3: a hyperthermophilic, acidophilic, obligate anaerobe
A. They would all be capable of growing in the presence of O 2.
B. They would all be capable of growing at temperatures >50°C.
C. They would all grow well in high salt conditions.
D. They would all grow well at acidic pH.
E. None of A -D is true.
None of A -D is true.
The growth profiles of three bacterial strains with
respect to temperature are shown. Which strain
shows the widest range of thermotolerance?
A. Strain X
B. Strain Y
C. Strain Z
* tolerance vs. optimal growth
Strain Y
A halophilic bacterium would likely be living in
an external environment that is _________with
respect to its’ intracellular environment.
A. hypotonic
B. isotonic
C. hypertonic
Hypertonic
Phosphate is a macronutrient
requirement for life. It is found in:
A. all nucleic acids
B. all proteins
C. all carbohydrates
D. all lipids
all nucleic acids
For most bacteria, increasing the amount of this
nutrient to a growth medium will typically lead to
a significant increase in cell yield. Which nutrient
would this be?
A. nitrogen
B. carbon
C. sulfur
D. phosphorous
E. iron
Carbon
Shown are the growth
zones in a tube of fluid
thioglycollate medium.
Match the zone to the type
of microbe found there.
C. facultative 2-aerobic 3-microaerophilic 4-anaerobic
Three different bacterial strains were grown on
a fluid thioglycollate medium. Which one has the
least amount of SOD, catalase, and/or peroxidase?
A. A
B. B
C. C
D. A, B, and C all possess
these enzymes.
B
Four different bacterial strains were grown on a fluid thioglycollate medium. The aerotolerant
anaerobe is found in tube ___.
A
B
C
D
B
What kind of growth medium is this?
A. Defined
B. Complex
C. Selective
D. Differential
Complex
What is the carbon source in
nutrient agar?
Peptone
Beef extract
What is the nitrogen source in
nutrient agar?
Peptone
Beef extract
A bacterial batch growth curve is shown.
Which of the following among A-D is false?
A. Changes in cell size occur during phases 2 and 3
B. Exponential changes in
cell numbers occur during
phases 2 and 4
C. Acclimation phase = 1
D. Most likely to begin forming endospores: phase 3
E. None of A – D is false.
Which features are applicable to biofilm
formation?
A. Stationery phase of growth
B. Endospores
C. Presence of a surface
D. Fimbriae/pili
E. Two of the above
