Studied by 41 PeopleWhy Carbon (3)
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Why Carbon (3)
makes polymers
does not go in rocks
becomes atmosphere
Why water
large liquid zone (H bonds)
volatile
abundant (h and O like to bond)
Drake Equation
N = R fp ne fl fl fc L
origin of life heterotrough
cold eat organic ocean
Autotrophic orign
hydrothermal vent methanogenesis
metabolism first
cycles of chemical reactions --> metabolism -> genetic molecules
RNA first
Genetic soup -> genetic molecule -> RNA -> DNA/protien
IW redox buffer
Iron Winstite Fe + O2 --> FeO Fe2+ --> Fe2+ very reduced moon/mars
FMQ redox buffer
Faylite Magnetite Quartz 3Fe2SiO4 + O2 --> 2Fe3O4 + 3SiO2 Fe3+ --> Fe3+, Fe2+ middle reduced Today's Earth
PPM redox buffer
pyrrhotite, Pyrite, Magnetite 6FeS + 2O2 --> 3FeS2 + Fe3O4 oxidized crust/ocean/hydrothermal vents/early earth
DNA decay
Cytosine --> uracil The nitrogen carbon bond gets hydrolysed 1/2 life 17,000 years
Nucleic bases
Cytosine Uracil Guanine Thymine Adenine
Purines
Adenine Guanine
2 CN rings (4N)
Pyrimidine
Cytosine Uracil Thymine (Benzene C6H6)
1 CN ring (2N) (Cut the pyramid)
Purine Formation
(Adenine, Guanine) spontaneous photochemical hydrolysis of cyanide Adenine is 5 HCN's
System
Reduction of System
Ammonia
:NH3
alpha hydroxy acid
Cyano-hydrin
Formaldehyde
aldehyde
hydrocyanide
HCN
Aminoacid from striker (look like)
Could be Alanine or Glycine depending on the group
Alanine
amino acid with R group = CH3
Glycine
Amino acid with R group = H
Adenine Structure
A purine (DNA base) made of 5 CNs
Note: guanine is an extra hydration step
Methane
CH4
Pyrimidine synthesis
Harder to make than purine. One theory is instead of Base + sugar makes base and sugar together.
Chemical Polymerization
Connecting molecules together chemically
Thermal Polymerization
(unlikely) Drying out and readding water. 150 -180C exposures
Glycerol Nucleic Acid and Threose Nucleic Acid Pros and Cons
GNA and TNA
Simpler than RNA, but can be read by the same systems
Decays faster (Unstable)
Peptide Nucleic Acid
PNA
simple and easy to make
but not sugar backbone (v different)
HCN polymer
HCN is abundant and while spontaniously do it
too abundant so it's hard to control
Chondrules
Small inclusions in undiffernchaited metiories
Chondrites
Account for 84% of meteorites undifferentiated rock
Carbonaceous Chondrites
.5-5% carbon 2 - 10% H20
Pallasite Meteorite
Find in 1951. A stony iron, core mantel boundary.
Why is a methane atmosphere not sustainable
Methane photolyzes in UV on a 100 Myr timescale
Ribozome Protein/RNA
Need RNA more. RNA made Ribosome
Strings of Nucleic Bases are hard to make
Poly A is good, rest much worse. If add isomers only really short chains can be made
Uranium 238
Lead 206 4.5 Ga
Uranium 235
Lead 207 0.7 Ga
Stable Lead isotopes
Lead 204
Rubidium 87
48.6 Ga Strontium 87
Reverse Gyrase
Hydrothermal supercoiling adaptation used in PCR
On Axis circulation
350-370C 24 Km^3/yr Less and hotter Near MOR
Off Axis Circulation
150 avg C 560 km^3/yr More and Cooler Far from MOR
Magnetite
Fe3O4
Iron Oxide
FeO
