Origin of Life Flashcards
what is life>
a self sustaining chemical system capable of undergoing darwinian evolution
important elements for life
liquid water= chemical reaction medium
organic polymers= [nucliec acids/proteins]= replicaiton and catalysis
fundamental properties of live
driving force metabolism herediety integrity energy excretion
driving froce
carbon sources; continous reactivity
metabolism
catalysis determines pathways
heredity
replication; needs high concentration of monomers
integretiy
cell boundaries need lipid synthesis
energy
power sources; to power anabolism for dna formation using ATP
ecretion
waste disposal; continous loss for equillibrium
key theories for origins of life
primordial soup (heterotrophic origins) pansmeria creationism sponteanous generation clay minerals
autotrophic:
black smokers
alklakine events
when was luca
4 bya
life dogma
inorganic matieral
organic matieral
protocells
cells
multicellular life
what are protocells
atp-energy systems
with some genetic matieral and a lipid membrane
primordial soup theory
proposed in 1920 by alexander oparin and jbs haldane
inorganic chemicals in high energy conditions in primodrial oceans developed into organic matieral by electrical charges
- high energy [uv], anoxic conditions
millery urey 1953
stanley miller conductd experiments to support the primordial soup theory by recreating the soup
using ammonia, methan, hydrogen and electrical chargees/uv light in anoxic conditions
produced organic matieral and rna [20 amino acids]
issues with the primordial soup
no thermodynamic driving fore [high entropy but low enthalpy]
no reducting atmospheric evidence with methane, hydrogen and ammonia
no chemical disqeqiullibrium in ocean and atmosphere; the end product has to b removed to disrupt the eqiullibrium
nothing to contain and concentratethe products
rate of formation on global scale unrealistic and low
atmosphere too thing; uv would have release products
gunter wachterhauser about primordial soup theory
its logically paradoxical and thermodynamicall incompatible
black smokers 1978
discovered in deep ocean with dense life surrounding vents by a us naval ship in galapagos
are dynamic and uneqiullibrated systems
produce metal sulphides (black smoke) in sea water tha tleads to acidic and hot conditions
composed of iron pyrites [fools gold]
sea water and water are charged with minterals and gases(hs2) to produce organic matter by carbon fixation of sulphub bacteria
hence oxygen and hydrogen sulphide combine to form water and sulphur
john baross + black smokers
diseqiullibrium is good but primorial earth had too little oxygen
wachterhauser + black smokers
reaction of hydrogen sulphife and iron; mineral iron pyrites produce energy ‘pyrite pulling’
pyrite formation= carbon monocide is maybe the intermediate of volcanic activity
critics of black smokers
not enough concentration of organic matieral to form rna and dna
too hot and acidic
no compartmentalization of organic mateirals
too low ph and life time
russel and serpentation
serpentation in vents
water and peridotite (olivine) combine to form serpentite, hydrogen and heat
hydrates oceanic crust which drives volcanic cycle and then tectonic acvitivty
seawater and magma; ocean ridges and volcanoes creating reducing environment converted to energy and hydrogen
alkaline hydrothermanl vents
2000 ‘the lost city’ discovrered by Deborah Kelly
microporous labaryynth structures thorugh which alkaline hydrothermal fluids flow to creatic acidic (proton rich) environment by a process of serpentinisation
carbon diocide and hydrogen react!
russel and hydrogthermal vents
they act as electochemical reactors with a flow of carbon
redoc gradient (300 mv) and temperature gradient (70c) and pH gradient (3-5 pH) across interconnected pores and an Iron Sulphide catalytic wall
these natural proton gradients; autotrophic cells use proton mebmranes across organic membranes adn vent pores (proton alklkaine fluids flow across barriers)
high hydrogen concetration; thermal cycling in vents and high pressure favours hydrogen and carbon dioxide formation and concentration
