introduction to metabolism: extremophilie Flashcards
1
Q
How do you define an extremophile? Why is the study of extremophiles important to the
study of evolution?
A
- bacteria and archea are the real extremophiles
- an extremophile is an organism that requires and thrives in extreme environements
- bacteria and archea have diverse metabolic pathways and can metabolize things eukaryotes cannot
- important to evolution because they can show us the diverse environements where life can exist. shows us that organisms can adapt and thrive in a variety of environments
2
Q
- How does the metabolic flexibility of Archaeans and Bacteria allow them to expand into more
extreme environments?
A
- they can metabolise things eukaryotes cannot
- for example, hydrogen or arsenic
3
Q
- List three different metabolic pathways (redox reactions) utilized by extremophiles.*****
A
1) aquificales- chemolithoautotrophicthermophiles used hydrogen oxidation : H2 + 1/2O2 –> H2O
2) methanothrophic archea used sulpher oxidation: S + 3/2 O2 –> SO3
3) oblifate anaerobe uses photosyntheic arsenic metabolism
4
Q
- Explain, with examples, how extreme environments determine the metabolic pathways that
extremophiles have adapted to use?
A
- different extreme environments are home to different extremophiles
5
Q
- Describe an Earth-based organism that would be an analogue to life on Mars. Substantiate
your reasoning
A
- deinococcus radiodurans
- can survive when exposed to lots of radiation
- Mars has a weaker atmosphere compared to Earth, so there is more exposure to radiation
- If these organisms can sustain radiation on Earth, there is a possibility of extremophiles on Mars
- D. radiodurans can also withstand a dry environements (Mars is very dry)
- D. radiodurrans could potemtially resemble an extremophile that could exist on Mars
6
Q
Yellowstone Hot Springs
A
- high temperatures (greater than 70 C)
- species of aquificales- chemolithoautotrophicthermophiles
- H2 oxidation
- greendragon hot sprngs with notable copper concentration
- conditions: greater thn 70 C, hydrogen concentration of 300nM, pH about 3
- H2 + 1/2O2 –> H2O
- they eat hydrogen
- the conditions of the hotspring were replicated in an acetate chamber. colonies were exposed to this enivronment
- the colonies were subjected to varying amounts of hydrogen sulphide and hydrogen
- when there was more sulphide, there was more diversity beacause there are extremophiles that can oxidize sulpher
- when sulpher concentration was decreased and hydorgen concentrate there by increased, there was mostly aquificales because they can oxidize hydrogen
- the oxidation of hydorgen releases more energy than oxidation of hydrogen sulphide
7
Q
Lake Vostok
A
- 1 million year old microbes from 4km under the ice
- a big lake found 3.5 km below the ice sheet
- They drilled a hole. in the hole they found younger ice deeper so it was concluded that there was a subgalcial lake making ice
- life forms were found that arent found anywhere else on earth. they were living undistuiribed; we had no idea they existed
- 98.8% based on ribosomal DNA
- microbe species
- geothermically catalyzed the environment. There organisms have metabolic processes
- it is hypothesized that there is a similar process to the organsims that produce bleeding ice.
- **see notes for reaction
8
Q
Deep Sea Vents
A
- CH4 and S oxidation at 120C
- cracks in the crust where the mantle reaches the crust. there is increased geothermic activity
- Found across regions of earth
methanogins found; methanotrophic archaea and sulpher reducing bacteria
-uses sulpher oxidation: S + 3/2 O2 –> SO3 - alternativley in symbiosis with methanogensis: 4H2 + CO2 –> CH4 + H2O
- methanogins and sulpher oxidizing bacteria are related because of their reactants and products. It is a cyclic cycle
- they thrive at over 100C. they require this for surviva. Take them in under 84C, they die
9
Q
Mono lake, California
A
- pH 10 and salinity 105 ppt (3 times the ocean)
- terminal (or genesis) point of ancient lake chain infused with lava flows
- home of photosyntheic arsenic metabolism
- the beach is hard due to increased salinity and crust salt pillars are exposed due to draining of the lake.
- obligate anaerobes found. they live in muddy, highly dense anaerobic place.
- **see notes for reaction
10
Q
acidophile
A
- an organism that grows best at acidic (low) pH values
- under 7
11
Q
alkaliphile
A
- an organism that grows best at high pH values
- above 7
12
Q
anerobe
A
- an organism that can grow in the absecence of oxygen
- oxygen is toxic
- can combine with an endolith
13
Q
endolith
A
an organism that lives inside rock or in the pores between mineral grains
- can combine with an anerobe
14
Q
halophile
A
an organism that requires high concentrations for salt for growth
15
Q
methanogen
A
an organism that prooduces methane from the reaction of hydrogen and carbon dioxide, member of the archaea
