Origin Of Life Flashcards

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1
Q

Steps in metabolism

A

Nutrient uptake
Nutrient processing
Waste elimination

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2
Q

Generative processes

A

Growth and reproduction (replication)

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3
Q

Responsive processes

A

Individual adaption
Immediate responses to environment
Population evolution

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4
Q

Control processes

A

Coordination

regulation

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5
Q

Structural organization

A

Cellular level

Organismal level

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6
Q

What was the first idea of origin or life and proposed by who

A

Spontaneous generation by Aristotle. “Living organism arise spontaneously from non-living matter”

Maggots formed from dead meat, lice product of sweat

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7
Q

What is biogenesis

A

Life can only originate from pre-existing life

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8
Q

Three things needed for life

A

Energy source
Raw materials
Suitable environment

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9
Q

What were the conditions in early earth

A

Extremely high temps
Diff atmosphere (water vap, nitrogen, co2, methane, ammonia, hydrogen, hydrogen sulfide were all reducing)
No liquid water
Little oxygen
As earth cooled water vapour condensed, hydrogen escaped

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10
Q

What were the energy sources on early earth

A

Sun (light, UV)
Volcanic eruptions
Lightning

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11
Q

What materials present on early earth

A
C
H
N
O
P
S

extraterrestrial sources

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12
Q

Scientists believe that first life form was made of RNA cause

A

RNA is self replicating molecule

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13
Q

Support for extraterrestrial sources on earth

A

Carbonaceous chondrites e.g. murchison meteorite contained disomer amino acids
ALH 84001 meteorite - believed to have martian bacteria

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14
Q

Describe the origin of life on earth by chemical evolution

A

Stage 1 - Abiotic synthesis of monomers (aka simple molecules)
Stage 2 - Formation of polymers ( putting simple monomers together to make smtg more complex)
Stage 3 - Packaging of polymers into protocols (packing into 1st cells)
Stage 4 - Self replication t

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15
Q

What does meros and pro to and A mean

A

Meros - part
Proto - first
A - absence

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16
Q

Descibe oparin’s hypothesis

A

Stage 1 - Spontaneous formation of monomers
Believed early earth had reducing atmosphere, and if combined with source of energy, simple molecules could combine into organic compounds.

17
Q

What did miller-urey find testing ocarinas hypothesis

A

In lab conditions similar to early earth (reducing atmosphere) he found one week later all 22 amino acids had been synthesized (sugar, pyrimidine and purine bases, AA, ATP). Showed organic molecules can for in a strongly reducing atmosphere

18
Q

Describe stage 2 of oparins hypothesis

A

Polymer formation
Monomers could have combined to form organic polymers. Same energy sources. Clay as substratum for polymerization? -> dropping sln of AA on hot clay results in spontaneous formation of polymers

19
Q

Describe stage 3 of oparins hypothesis

A

Protocells
Polymers aggregated into complex, organized, cell-like structures called protocells
Cell-like vesicles form spontaneously in the lab i.e. coacervate droplets, liposomes

20
Q

Describe protocells

A

Structural organization, simple homeostasis, simple reproduction, simple metabolism

21
Q

Step 4 of oparins theory

A

Self replication
Need two things: enzymes to catalyze reaction and a template
RNA

22
Q

RNA world? Describe RNA

A

Single stranded genetic material
Forms enzymes which accelerate reactions called ribozymes
Could have facilitated replication and reaction catalysis on early Earth

23
Q

Natural selection in an RNA world?

A

Variation among RNA strands due to copying error + Replication + Some strands better at competing for nucleotides and replicating
Natural select for shape, stability, replication accuracy & speed most suited to environment

24
Q

Describe protocols with different types of RNA

A

Protocells able to take up RNA with superior replication and catalytic abilities would have been more successful than those with inferior or no RNA.

25
Q

RNA vs DNA

A

RNA served as template for assembly of DNA nucleotides

DNA more stable genetic molecule

26
Q

5 problems with theory of chemical evolution?

A
  • Earths atmosphere may not have been reducing
  • Lightning bolts not likely sufficient source of power (electrons) as to drive early reactions to have enough electrons available would’ve needed 4 bolts of lightning per sec
  • Cell-like vesicles aka protocells form only when polymer concentrations are high
  • Chemical reactions do not continue in a net fwd direction if end products not removed (need a way to get end products out so reaction can keep going)
  • RNA very complex molecule, so could not have been original catalyst
27
Q

Other alternative than chemical evolution to origin of life?

A

Alkaline vents.