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55 Cards in this Set

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Two major nutritional groups
autotrophs heterotrophs
Autrotroph
-energy from:
-carbon from:
-energy from: sunlight or inorganic substrates
-carbon from: CO2
Heterotroph
include:
obtain energy from:
obtain carbon from:
nutritional requirements in:
include: all pathogenic microbes
obtain energy from: reduced carbon cpds (carbs)
obtain carbon from: reduced carbon cpds (carbs)
nutritional requirements in: host tissues except for Fe
Gropus of Bacteria based on ability to use 02 (4)
aerobes: require O2 for growth
anaerobes: grow only w/o 02 (strict rapidly killed by 02, vs aerotolerant)
facultative (anaerobes): will grow w or w/o O2
microaerophilic: grow only at lower %02 levels
Toxic end products formed in presence of oxygen (2)
hydrogen peroxide (H2O2)
superoxide anion (O2-)
Enzymes to detoxify toxic end products
Catalase: 2H202 --> 2H20

Superoxide dismutase: 202- --> H202 + 02
Relationship of CO2 on Bacterial Growth
CO2 required for growth of all bacteria
CO2 needed for which bacterial reactions?
biosynthetic (fatty acid biosynthesis)
What CO2 level needed for bacteria?
Greater than atmospheric CO2 needed for some pathogens (supply with CO2 incubator or candle jar)
3 Temperature Ranges of Bacterial Growth
1) Psychophiles
2) Mesophiles
3) Thermophiles
Psychophiles
range (temp)
obligate (location)
facultative (temp, association)
range: 0-25C
obligate - found in snow fileds and polar ice caps
facultative - grow best 25-30C, often associated with food spoilage, can contaminate vaccines and IV solns
Mesophiles
range (temp)
optimum (temp)
importance
range: 15-45C
Optimum 30-37C
Includes most pathogens
thermophiles
(range)
range 35-70C
Most pathogens grow best at pH:
6.8-7.2
Cardinal points of pH (3) and definition
Growth range defined by cardinal points
1) minimum pH - no growth below pH
2) maximum pH - no growth above pH
3) Optimum pH - point where best growth occurs
Pathogens grow best at __________ pressure equal to __________ saline.
____ mM NaCl
Exception
osmotic pressure
physiologic saline
150 mM NaCL
some halotolerant grow up to 7.5 % NaCl
Bacterial growth
method
description
Method: binary fission
Description: cell doubles in mass and divides into two equal daughter cells
Generation time
amount of time for cell number to double (depends on species, growth medium and growth temperature)
Measurement of growth (3)
1) change in turbidity using spectrophotometer
2) dilutions and plate counts of viable cells
3) coulter counter - count bacteria-sized particles - yields total counts
Bacterial Growth curve phases (4) picture?
1) lag
2) exponential (log)
3) stationary
4) death
Phase of Bacterial growth (lag)
2pts
1) period of atdaptation to new environment
2) little or no increase in cell numbers
Phase of Bacterial growth (exponential or log)
1 pt
cells double at a constant rate
Phase of Bacterial growth (stationary)
2pts
1) nutrients become depleted or metabolic waste products accumulate
2) growth occurs - balanced by cell death
Phase of Bacterial growth (death)
1pt
numbers of viable cells decrease
Four main components of bacteriological growth media
1) peptones
2) infusions and extracts
3) agar
4) fermentable sugar
Four main components of bacteriological growth media (peptones)
acidic or enzymatic hydrolysates or proteins, usually casein
Four main components of bacteriological growth media (infusions and extracts) (1pt, 3 examples)
water soluble fractions - crude source of nutrients
-meat
-plants
-yeast (source of vit B)
Four main components of bacteriological growth media (agar)
solidifying agent (1.5%)
Types of Bacteriological Media (3)
1) enrichment media
2) selective media
3) differential media
Types of Bacteriological Media (enrichment)
importance:
favors growth of a microbe present in low numbers
Types of Bacteriological Media (selective)
contains:
favors:
inhibits:
contains: chemicals such as 7.5% NaCl, detergents and heavy metals
favors: growth of one organism
inhibits: growth of other organisms in specimen
Types of Bacteriological Media (Differential media)
contains:
contains: indicators to identify bacteria e.g. blood or dye
Metabolism defn
Chemical Reactions in Living Cells
Catabolic pathways characteristics (3pts)
1) produce ATP
2) Oxidative - remove H's and e's from nutrients
3) produce intermediates
Anabolic pathways characteristics (3pts)
1) require ATP
2) Reductive (use H's supplied by NADH and NADPH)
3) Start with intermediates
Number of Stages of Fermentation?
2
First step of Fermentation:
Primary pathway of Fermentation
Embden-Meyerhof net yield:
Entner-Doudoroff net yield:
Pentose Phosphate net yield:
Primary pathway of Fermentation: convert glucose to pyruvate Embden-Meyerhof net yield: 2ATP 2NADH/glucose
Entner-Doudoroff net yield: 1ATP + 1NADH
Pentose Phosphate net yield: OATP, NADPH, 4 and 5 C sugars
Second step of Fermentation
forms alcohols, acids and other
Respiration # of Stages?
3
First step of Respiration
primary pathway, same as fermentation: glucose --> pyruvate
Second step of respiration
Oxidation of pyruvate via TCA cycle --> 1ATP, 4NADH 1 FADH2
Third Step of Respiration
ETS
1 NADH yields 3 ATPs
1 FADH2 yeilds 2 ATPs
Electron Transport System associated with:
bacterial cell membrane
Electron Transport System description
Electrons passed through ETS in a stepwise fashion and energy released is used to generate ATP - due to different oxidation or reduction potentials
Electron Transport System carriers and transfer molecules (3)
1) Flavoproteins (contain cofactors derived from riboflavin)
2) Coenzyme Q / ubiquinones
3) Cytochromes (cofactor is porphryin - Fe complex)
Glycolysis Produces:
TCA cycle produces:
Total:
Glycolysis produces:
2 ATP
(2 NADH =) 6ATP
TCA cycle produces:
(4NADH = ) 12ATP
(1FADH = ) 2ATP
(1GTP = ) 5ATP

Total:
2 pyruvates/glucose:
38 ATP
Integration of Anabolism and Catabolism

Biosynthetic reactions in cells require what 2 things?
ATP and NADPH
Integration of Anabolism and Catabolism

Define: amphibolic pathway:
direction of pathway depends on needs of cell for pathways that produce energy as well as biosynthetic intermediates
Triple Sugar Iron (TSI) Agar Reactions
Detects:
Detects: fermentation of 3 sugars: lactose and sucrose at 1% and glucose at 0.1%
TSI possible fermentation patterns: (3)
Bacteria ferment:
1) none of the sugars
2) only glucose
3) glucose and one or both of the other sugars
TSI metabolism describe on slant and butt
slant: aerobic metabolism
butt: anaerobic metabolism
TSI detects what other than fermentation?
Hydrogen sulfide production
Interpretation of TSI Reactions:
yellow butt, red slant
acid butt, alkaline slant
catabolism of only glucose --> lactic acid since butt is anaerobic. acid makes butt yellow
growth on peptones raises pH on slant
Interpretation of TSI Reactions:
yellow/yellow
acid butt and acid slant
10 fold higher concentration of the other sugars resuls in significantly more acid if either/or both are catabolized
Interpretation of TSI Reactions:
red/red
alkaline butt and alkaline slant
-no utilization of sugars
-degredation of peptones aerobically and anaerobically