origins of lifee on Earth - steve Flashcards
what was the first genetic code lilely to made out of? small proteins ds. DNA ss. DNA ss. RNA ds. RNA
RNA - single stranded
whilst less stable than DNA, it has catylyst abilty!
and can be replicated
what happened to gas composition during the great oxygenation event?
oxygen levels increased
as a result methane dropped as oxygen reacted with it to produce CO2
> this also may have contributed to the many major ICE AGES due to the reduced greenhouse effect
approxumate age of earth? BYA 2.5 3 3.5 4 4.5
4.5 BYA
BYA = billion years ago
what was earths environment like in hadeon eon ERA?
toxic, anaerobic, high tides, spinning, violent, smoogy
just buzzwords really
what were the flaws in miller and ureys primordial soup experients?
> spark of energy = lightening
cocnetratin - ocean is dilute
unlikley to happen spontaneously and more likely to detroy
gas compositions are different
conditoons of a ‘‘black smoker’’ vent
ACIDIC, high in sulfur, high pressure, low oxyge, iron pyrites
why are alkali vents the most current theory for first life?
small chambers can overcome concetration issue
proton gradient can be estalbisehd with acid exterior
had the components for aa synthesis (as seen in M-U experiement)
Fe- S can act as catalyst
Which of the following is not provided by a mineral cell? A Redox potential B Relatively low water potential C A stable environment D High concentrations E Catalyst
OPTION C
That provide a suitable environment for a reaction to take place and possibility of amino acid/ nucleic acid formation.
for the mineral cell to have a low water potential it would have to match the dilute ocean - COMMON SENSE
What is primordial soup theory of evolution?
A Basic compounds of life (Amino acids, nucleic acids, carbon based compounds) react to form the primordial organisms.
B Key elements of life (found in puddle or “soup”) reacted to form organisms after “spark of life” from energy source.
C The key elements of life (found in a puddle or “soup”) reacted to form basic compounds for life (Amino acids, Nucleic acids, Carbon based compounds etc) after a “spark of life” from energy source (lightning).
OPTION C
> just mroe detailed really
What is the MINERAL CLAY theory for the origin of life?
A Clays contained biomolecules that could synthesised to form amino acids
B Water bearing clays became vessels for replication and patterning due having mineral salts for catalysis/processes
C Clay were vessels for biomolecules that eventually became the first organisms
OPTION B
name the limitations of miller urey expwroents
> ealry earth gass composition of atmosphere most likely CO2, N2, H2S and SO2, these gases can’t make amino acids and only traces of the Miller-Urey gases used.
unlikely to happen spontaneously.
Lightning can create but can also destroy, not a reliable catalyst
Concentration problem - hard for things to react
which plantets atmosphere was miller-ureys experiement based on? A mars B earth C juspiter D saturn E venus
jupiter!
Replicated the conditions early (Hadean) earth atmosphere based on Jupiter.
Found - Amino acids formed via formaldehyde
Which of these is not molecular evidence for the endosymbiosis theory?
A Ox-phos complexes in semi-autonomous organelles are similar to prokaryotes’
B All photosynthetic organisms have the same conformation of photosystems
C Photosynthetic mechanisms in chloroplasts are nearly identical to cyanobacteria
D Division proteins and mechanisms e.g. FtsZ, MinD, MinE
E Nuclear genes that affect organelles are homologous to cyanobacteria
OPTION B
this is not comapring prokary and chlorplasts/plants and only considers plants only!
what was the first human species ? A Homo erectus B Homo habilis C Homo sapiens D Neanderthals E Homo naledi
homo naledi! - 2.8MYA
> hablis is a ditinct species but radiated quickly to erectus
spaien and neanderthals coexisted
How old is the universe?
- 6 billion years old
- 5 billion years old
- 4 billion years old
- 7 billion years old
- 2 billion years old
13.7 BILLION year old
