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5 Cards in this Set
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In the Hadean period, around 4 BY ago, the young caused Strong UV on the earths surface, what impact would this have had in terms of life? |
No atmosphere to protect from UV, would have damaged/destroyed DNA, thus DNA-based life must have arose somehwere that was protected from the worst of suns UV. |
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What makes people think that life may have arose from deep sea thermal vents? |
The alkaline vent water meets acidic seawater, setting up a proton gradient.
It is thought that the proton gradient may have supplied the energy needed to fuel first self-replicating molecules. |
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What evidence/ thoughts are there that life began as RNA molecules. |
DNA is just an inert store
RNA can copy itself
Bits of RNA can acts as enzymes
RNA is its own genes (then that info is stored in DNA) |
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For life to arise, its components must be contained, constrained and protected.
How can life have arisen without something for it to occur within? |
Best idea is that of Protobionts,
These lipid-based molecules occur spontaneously.
They can also 'repoduce,' and metabolise, they conditions within them are suitable for RNA to replicate.
The other thought is that early life may also have arisen from tiny pores in rocks. |
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What was the relationship between methanogenic bacteria and cyanobacteria?
How is thought that the 'great-oxidation event,' occurred? |
First prokaryotes thought to have been metane-producing bacteria.
The effect of their metabolism kept oxygen conc stable (.001% of todays)
The first photosynthetic bacteria arose, they started producing oxygen.
The methanogenic bacteria consumed the oxygen produced, so again the levels were constant.
The great oxidaion event was not caused by |
