A2.1 Flashcards
when earth first originates the gasses were
mathane e ammonia, no o2 so no ozone layer
earths core was forst
molten so more movement there was a smaller magnetic field and more cosmic + sun radiation cause
the earth had a reducing atmosphere cause
there were many reducing elements which gave electrons and started chemical reactions
endocytosis
cell process where substances are brought into cell
spontaneous origin of cell 1)
simple organic molecules
like amino acids and hydrocarbons chains formed
spontaneous origin of cell 2) chemical reactions were
accelerated by catalysts
spontaneous origin of cell 3)
larger organic molecules like
RNA and phospholipids were assembled from smaller molecules
spontaneous origin of cell 4) some of these molecules like
rna were able to self replicate
spontaneous origin of cell 5) formation of a
mebrane compartment was able to give the cell a diffrent internal chemistry to the outside, allowing for optimum temperatures to be done
protocell
simple self organised cell like structure belived to the the first cell on earth
in 1952
2 scientists miller e urgy stimulated earth pre biotic conditions to prove spontaneuous formation of organic molecules
the miller urgy system inclued
water for ocean stimulator
inert gas to add h, methane e ammonia
electrical sparks- to show electrical storms
in the experiment, water was vaporised, run througb gases and
electrical sparks, condensed and the droplets collected represented primodrdial soup and had organic monomers
to make a cell mebrane
fatty acid spontaneously merged to form spherical bilayer
however, now we think
the atmosphere was less reducign than miller urgy thought which canges the outcome
it is thought rna was the
basic for first cell formation, acting as catalyst and genetic materialot
other hypothesis on how cells originated
metabolism first, the sulfir world and the lipid world
the metabolism first theory
like begain with a simple reaction and formed metabolic paths
the sulfur world theory
first lif forms were based on fe sulfur
the lipid world theory
the lipid bilayers evolved before rna, providing protective layers
3 domains of life
bacteria
archaea
eukaryota (forms from the other 2)
they have found
355 genes thougbt to been found in luca
LUCA
last universal common ancestor
rna genome single celld
luca existed
3.5-2.5 billion years ago and was in hydrothermal vents rich with h and minerals , was annaerobic
phylogenetic analysis
provides indepth understanding of how species evolved thorugh genetic changes
rna theory
it could
replicate from ribozymes and catalyse protine synthesis
spontaneous origin of cells
- simple molecules like like amino acids and hydrocarbons chains formed
2) chemical reactions were
accelerated by catalysts
3) larger organic molecules like
RNA and phospholipids were assembled from smaller molecules
4) molecules (rna) to self replicate
5) formation of a
mebrane compartment
