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Flashcards in Origin of Life Deck (32):
1

what is life>

a self sustaining chemical system capable of undergoing darwinian evolution

2

important elements for life

liquid water= chemical reaction medium

organic polymers= [nucliec acids/proteins]= replicaiton and catalysis

3

fundamental properties of live

driving force
metabolism
herediety
integrity
energy
excretion

4

driving froce

carbon sources; continous reactivity

5

metabolism

catalysis determines pathways

6

heredity

replication; needs high concentration of monomers

7

integretiy

cell boundaries need lipid synthesis

8

energy

power sources; to power anabolism for dna formation using ATP

9

ecretion

waste disposal; continous loss for equillibrium

10

key theories for origins of life

primordial soup (heterotrophic origins)
pansmeria
creationism
sponteanous generation
clay minerals

autotrophic:
black smokers
alklakine events

11

when was luca

4 bya

12

life dogma

inorganic matieral

organic matieral

protocells

cells

multicellular life

13

what are protocells

atp-energy systems
with some genetic matieral and a lipid membrane

14

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

15

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]

16

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

17

gunter wachterhauser about primordial soup theory

its logically paradoxical and thermodynamicall incompatible

18

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

19

john baross + black smokers

diseqiullibrium is good but primorial earth had too little oxygen

20

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

21

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

22

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

23

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!

24

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

25

chemiosimosis and the vents

-movement of protons over membrange

natural concentration of organic molecules in the walls; allows for a concentrated amount

- direct synthesis of organic molecules and energy release

26

why are hydrothermal vents a good hypthesis for life

- excretion solved by venting and diseqiullubrum
- replication; possibile in porous vents
- metabolism; catalysis by the minerals
-driving force; carbon diocide and hydrogen cycling in alkaline vents
- energy; natural proton gradients


- disequillibrium and promoted volcanism on planet
- provides hydrogen to react with carbon diocide
- have been venting twice as longer as black smokers
- probably everywhere on primoridail earth as more iron available
- can produce acetyl thioester; which is a starting point for organic molecules

methane is present

metalloproteins can act as enzymmes

they can synthesise AA, HC and pyruvates

27

what minerals are catalyzed in hydrotherman alkaline vents

nitrogenase and hydrgoenase; are natural inorganic membranes that form; similar to ferredocin of krebs cycle

28

nick lanes critique of primordial soup

-assumes origion of life and origin of replication the same thing
-rnad world as catalysis andr eplication site but not ONLY replication origines as metalloproteins also catalyzie

- no obvious source of energy in soup
-uv light also destroys and no life today uses atp from uv
-soup at thermodynamic equqiilibrium hence to internal free neergy to drive chemical reactions in energy flux
- contentration too dilute or pdoucts in soul

29

chemiosmosis

natural proto gradients across an ionrganic membrane at 200 mv proton force simlar to modern cells

energy from o cidtation of NADH generates a prodton gradient across a membrane to drive synthesis of atp using proteins

30

atp

adp + pi; using atp synthase

31

atp synthase

ancestral and evolved in vents;
harneed natural proton gradients to create ATP after evolving in vents using inorganic membrane to form protocells

32

protocells evolution

used chemiosimis but then to leave vents had to become austonomous and therefore produce self ATP and generate own proton gradients