L8: Extreme Habitats + Metabolism

Question 1

What is the relationship in extreme habitats

Answer 1

extreme = strong environmental filter
deterministic community
lower richness + diversity

Question 2

4 Metals in metal respiration

Answer 2

1. Mercury
2. Arsenic
3. Chromium
4. Uranium

Question 3

What is shweanella

Answer 3

• can reduce any substrate
• bioremeditation
• mineral cycling

Question 4

Discuss Uranium respiration + application

Answer 4

• Uranium VI as TEA very radioactive + soluable => U IV
• But U IV is insoluable and removable

Question 5

Explain chromium respiration

Answer 5

• ChVI is industrial waste product
• when the sulfate is low: SRB reduces ChVI => CIII which is lexx toxic

Question 6

Discuss arsenic bioremediation

Answer 6

• Arsenite+3: most toxic + soluable, use as ED for anoxygenic photosynthesis
• Arsenate: common in mesophilic environments, less soluable, TEA for anaerobic respiration

Arsenite oxidase: good makes less soluable + toxic
Arsenate reductase: bad makes more soluable +

Question 7

What is dehalorespiration

Answer 7

• reductive halogenation that requires reductive dehalogenases
• can use H2 as ED + halogenated C as EA
• harmless anions released

Question 8

Mercury Cycle

Answer 8

• biomass burning + volcanoes put mercury into atmosphere, this can dissolve to atmosphere and elemental not that bad
• organisms oxidse it to mage Hg2 => MeHg, which is bad and bioaccumilates
• SRB can reverse

Question 9

Tell me about Plastic Degradation

Answer 9

• bacteria secrete extracellular enxymes that degrade plastic
• the smaller monomer can go into the cell and hydrolysed, released carbon + electrons
• carbon goes to biomass, e- for NADH through electron transport chain

Question 10

What is MIC
4 examples

Answer 10

microbially influences corrison
SRB+ iron RB + acid prodcuing bacteria
1. IRB, SRB can make iron sulfide from solid iron and sulfate = rust
2. Sulfur OB oxidide suflide to form sulfurc acid = corrosive

Question 11

How can microbes be used to fuel cells

Answer 11

1. Bacteria on oxides anode to form electron donor containing substrate
2. The Bacteria reduces the anode as TEA
3. e- flow makes electrical current
4. e- reduce oxygen to H2O in cathode
5. removal of e- from cathode = continious flow
6. Ions flow through permeable membrane to maintain charge balance

Question 12

Challenge of microbieal cells

Answer 12

1. anode is not soluable = how do e- go from bacteria to anode
2. anode must be anaerobic or reduce O2

Question 13

What are 3 mechs for transfering e- to anode

Answer 13

1. Direct contact: e- deposited with membrane bound enxymes
2. Direct Contact: e- transfered by conductive pili
3. E- transfered by e- shuttle from cell operator or bacteria

Question 14

3 Examples of microbial biofeuls

Answer 14

1. Ethanol produced from fermentation
2. Biodisel produces from agal plates
3. Hydrogen has for many processes

Question 15

Challenges of microbial biofuels

Answer 15

• developing infrastructure to produce commerical scale
• engines to feuls the plants
• cost