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55 Cards in this Set
- Front
- Back
Two major nutritional groups
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autotrophs heterotrophs
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Autrotroph
-energy from: -carbon from: |
-energy from: sunlight or inorganic substrates
-carbon from: CO2 |
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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 |
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Gropus of Bacteria based on ability to use 02 (4)
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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 |
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Toxic end products formed in presence of oxygen (2)
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hydrogen peroxide (H2O2)
superoxide anion (O2-) |
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Enzymes to detoxify toxic end products
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Catalase: 2H202 --> 2H20
Superoxide dismutase: 202- --> H202 + 02 |
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Relationship of CO2 on Bacterial Growth
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CO2 required for growth of all bacteria
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CO2 needed for which bacterial reactions?
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biosynthetic (fatty acid biosynthesis)
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What CO2 level needed for bacteria?
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Greater than atmospheric CO2 needed for some pathogens (supply with CO2 incubator or candle jar)
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3 Temperature Ranges of Bacterial Growth
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1) Psychophiles
2) Mesophiles 3) Thermophiles |
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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 |
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Mesophiles
range (temp) optimum (temp) importance |
range: 15-45C
Optimum 30-37C Includes most pathogens |
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thermophiles
(range) |
range 35-70C
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Most pathogens grow best at pH:
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6.8-7.2
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Cardinal points of pH (3) and definition
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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 |
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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 |
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Bacterial growth
method description |
Method: binary fission
Description: cell doubles in mass and divides into two equal daughter cells |
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Generation time
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amount of time for cell number to double (depends on species, growth medium and growth temperature)
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Measurement of growth (3)
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1) change in turbidity using spectrophotometer
2) dilutions and plate counts of viable cells 3) coulter counter - count bacteria-sized particles - yields total counts |
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Bacterial Growth curve phases (4) picture?
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1) lag
2) exponential (log) 3) stationary 4) death |
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Phase of Bacterial growth (lag)
2pts |
1) period of atdaptation to new environment
2) little or no increase in cell numbers |
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Phase of Bacterial growth (exponential or log)
1 pt |
cells double at a constant rate
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Phase of Bacterial growth (stationary)
2pts |
1) nutrients become depleted or metabolic waste products accumulate
2) growth occurs - balanced by cell death |
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Phase of Bacterial growth (death)
1pt |
numbers of viable cells decrease
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Four main components of bacteriological growth media
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1) peptones
2) infusions and extracts 3) agar 4) fermentable sugar |
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Four main components of bacteriological growth media (peptones)
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acidic or enzymatic hydrolysates or proteins, usually casein
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Four main components of bacteriological growth media (infusions and extracts) (1pt, 3 examples)
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water soluble fractions - crude source of nutrients
-meat -plants -yeast (source of vit B) |
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Four main components of bacteriological growth media (agar)
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solidifying agent (1.5%)
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Types of Bacteriological Media (3)
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1) enrichment media
2) selective media 3) differential media |
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Types of Bacteriological Media (enrichment)
importance: |
favors growth of a microbe present in low numbers
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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 |
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Types of Bacteriological Media (Differential media)
contains: |
contains: indicators to identify bacteria e.g. blood or dye
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Metabolism defn
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Chemical Reactions in Living Cells
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Catabolic pathways characteristics (3pts)
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1) produce ATP
2) Oxidative - remove H's and e's from nutrients 3) produce intermediates |
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Anabolic pathways characteristics (3pts)
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1) require ATP
2) Reductive (use H's supplied by NADH and NADPH) 3) Start with intermediates |
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Number of Stages of Fermentation?
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2
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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 |
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Second step of Fermentation
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forms alcohols, acids and other
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Respiration # of Stages?
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3
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First step of Respiration
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primary pathway, same as fermentation: glucose --> pyruvate
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Second step of respiration
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Oxidation of pyruvate via TCA cycle --> 1ATP, 4NADH 1 FADH2
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Third Step of Respiration
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ETS
1 NADH yields 3 ATPs 1 FADH2 yeilds 2 ATPs |
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Electron Transport System associated with:
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bacterial cell membrane
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Electron Transport System description
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Electrons passed through ETS in a stepwise fashion and energy released is used to generate ATP - due to different oxidation or reduction potentials
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Electron Transport System carriers and transfer molecules (3)
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1) Flavoproteins (contain cofactors derived from riboflavin)
2) Coenzyme Q / ubiquinones 3) Cytochromes (cofactor is porphryin - Fe complex) |
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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 |
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Integration of Anabolism and Catabolism
Biosynthetic reactions in cells require what 2 things? |
ATP and NADPH
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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
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Triple Sugar Iron (TSI) Agar Reactions
Detects: |
Detects: fermentation of 3 sugars: lactose and sucrose at 1% and glucose at 0.1%
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TSI possible fermentation patterns: (3)
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Bacteria ferment:
1) none of the sugars 2) only glucose 3) glucose and one or both of the other sugars |
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TSI metabolism describe on slant and butt
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slant: aerobic metabolism
butt: anaerobic metabolism |
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TSI detects what other than fermentation?
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Hydrogen sulfide production
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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 |
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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 |
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Interpretation of TSI Reactions:
red/red |
alkaline butt and alkaline slant
-no utilization of sugars -degredation of peptones aerobically and anaerobically |