microbes

Question 1

cyanobacteria

Answer 1

• Do oxygenic photosynthesis
• Only bacteria that can produce water bc capable of photolysis
• can fix nitrogen

Question 2

1. Pelagibacter ubique

Answer 2

• Oligotrophs, can only be grown w/ v low conc
• Found in ocean

Question 3

1. Anabaena

Answer 3

• Filamentous cyanobacteria
• Oxygenic phototrophs
• Has heterocysts for N fixation

Question 4

azotobacter

Answer 4

• Nitrgoen fixing, obligate aerobe bacterium that is regularly found in soil but in low numbers
  
  1. Want to isolate by eliminate by removing sources of nitrogen
• It’s a diazotroph, it fixes N2 via nitrogenase enzyme
• Able to use annitol as sole carbon source (kinda unusual)
  
  1. Use N-free Mannitol agar

Question 5

Bacillus

Answer 5

• Gram pos
• Can form endospores
• aerobic or anerobic??

Question 6

clostridium

Answer 6

• Obligate anerobe
• lack ETC
• Fermenter
• Can form endospires

Question 7

mycbacterium

Answer 7

obligate aerobe

Question 8

e.coli

Answer 8

• Facultative anaerobe
  
  • Gives positive nitrate reduction test (NO₃^- reduced to NO₂^-)te nitrate then oxidized by lithotrophs
  • Nitrate as TEA doesn’t give as foo energy yield
  • Neg for oxidase test bc doesn’t use cytochrome oxidase has diff cyt

Question 9

1. Staphylococcus aureus

Answer 9

Facultative anaerobe (suvive with or without but preference is with)

Question 10

lactic acid bacteria

Answer 10

• Lack ETC, obligate fermenters
• atp just from substrate level phos

Question 11

1. Streptococcus

Answer 11

• Aerotolerant anerobes,
• Obligate fermenters
• Use central pathways but not ETC so no oxidative phosphorylation
• Use TCA only for building bloks not for ATP or reducing power
• Don’t have catalase but do have peroxidase
  
  1. Product of braking down H2O2 is not oxygen (in catalase it is)

Question 12

campylobacter

Answer 12

microaerophile

Question 13

1. Desulfovibrio

Answer 13

• Sulfate reducing bacterium & hydrogen oxidizer chemoheterotrphs
• Can use H2 as energy source and sulfur as the TEA, this gives substancial energy
• can grow heterotrophically or use hydrogen as energy source, either case tho carbon source is organic

Question 14

1. Bacillus psychrophilus

Answer 14

• Psychrophilc bacteria
• Optimal growth below 15

Question 15

1. Thermus aquaticus

Answer 15

• Thermophilic archea
• Optimal growth 45-80

Question 16

1. Pyrococcus

Answer 16

• Hyperthermophilic archea
• Op grow above 80

Question 17

1. Thermotoga

Answer 17

• Hyperthermophilic bacteria
• Op growth above 80

Question 18

1. Acidithiobacillus ferrooxidans

Answer 18

Iron oxidizer, oxidizes ferrous iron to ferric iron

Question 19

1. Natronobacterium

Answer 19

• Halophilic alkaliphile
• Archea
• Have bacteriorhodopsin (light driven proton pump)
• Have a proton sponge (high density of negative charges @ alkaliphicic cell surface
  
  1. Do to prevent dissipation of proton motive force
• Also uses sodium motive force to take advantage of salty conditions to power ATP synthase

Question 20

1. Halobacterium salinarum

Answer 20

• Extreme halophile
• Grows in 13-15% NaCl, found in like great salt lake, dead sea and salterns
• Uses bacteriorhodopsin which is red so anywhere they grow is pink
• Evoluntionarly distinct form others

Question 21

1. Methanogens

Answer 21

• Anaerobic archea, combine H2 and CO2 to produce methane
• Oxidize hydrogen gas to acetate to make methane

Question 22

1. Methanotrophs

Answer 22

Oxidize methane

Question 23

Syntrphus

Answer 23

1. • Anaerobic bacterium Thermodynamic extremophile
   • Secondary fermenter, generates H2 (pos delta G)
   • Does secondary fermentation, endergonic reaction which produces hydrogen gas, hydrogen gas is then oxidized by a methanogen to produce methane **methane production always favourable
   • **secondary fermenters are essential to complete the anaerobic C-cycle

Question 24

1. Peptone iron agar

Answer 24

• Detects for proteolytic bacteria that produce H2S by reducing cysteine as an energy source (or thiosulphate) is basis of activity for desulfhydrare – removed sulfhydrul group reducing it to H2S
• Detected by black ppt

Question 25

1. Sugar fermentation tests

Answer 25

1. Oxidation fermentation test (aka high leifsons)
   
   1. Diff basis of fermentative or oxidative metabolism of carbohydrates
2. Carbohyrate fermentation
   
   1. Fermentation medium consists of nutrient broth to meet growth req, bromocresol purple (ph indicator) and specific carbohydrate
   2. When carbohydrate is fermented acids & gases are relased
      
      1. Fermentation will cause colour change to yellow and presence of gas as air bubbles

Question 26

1. N-free mannitol broth & agar

Answer 26

1. Can be used for enrichment
2. No nitrogen source, must be able to fix N2 (diazotorphs)
3. Mannitol = only carbon source
   
   1. Kind of unusual for bac to only rely on mannitol
4. Can use to isolate Azotobacter

Question 27

1. Nitrate broth

Answer 27

1. Detects of Enterobacteriaceae which can perform aerobic, anaerobic and fermentation – can reduce nitrate under anaerobic conditions to nitrite
   
   1. Can reduce nitrate to nitrite under anerobic conditions
2. In a Durham tube inoculated w test bacterium and incubated
3. Nitrite detected by red or pink
   
   1. If not present nitrate either not reduced or reduced past by full denitrification
   2. Test by adding zinc (will determine if nitrate was reduced past nitrite) that causes any remaining NO3 to be reduced to nitrate which would then react with reagents in tube and give red colour
   3. If no red formed then it’s a positive test as nitrate was removed by denitification

Question 28

1. BG11 & BG11₀

Answer 28

1. BG11 is a selective defined medium to grow photosynthetic cyano bacteria
   
   1. Oligotrophic nutrient conc
   2. No organic carbon source
2. BG110 more selective
   
   1. No nitrogen source

Question 29

1. MacConkey agar

Answer 29

• Selective and differential
• Isolates for gram engative and enteric bacilli
• Differentiation based on lactose fermentation
  
  1. Lactose fermenters will turn pink

Question 30

1. Blood agar

Answer 30

1. Differential and enriched medium
2. For fastidious organisms like streptococci