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The Origin of Life

Terms in this set (23)

Compartment/ growth
Metabolism (limited homeostasis)
Genetics/ evolution
What do all cells have?
Differentiation of cells
Communication
Genetic exchange
Motility/ react to stimuli
Complex homeostasis
What do some cells have?
Metabolism
Cells take up nutrients, transform them, and expel wastes
(1) Genetic (replication, transcription, translation)
(2) Catalytic (energy, biosyntheses)
Prokaryotic cell
Simplest cells
(1) existing biology working backwards towards a common point
OR
(2) chemistry building up to a cell
The origin of life can be studied from...
4.4 billion years ago
When did molten rock solidy to form the oldest rock?
3.8 billion years ago
When did the oceans form?
Biofilms of Cyanobacteria
What are the Earth's oldest fossils made out of?
stromatolites (3.5 billion years old)
What are the oldest fossils, and how old are they?
DNA and RNA (translation and transcription)
Proteins, enzymes- sophisticated metabolism
Lipid membranes, cell walls, binary fission
List characteristics of stromatolites
Last Universal Common Ancestor
What does LUCA stand for?
RNA and DNA
Metabolism: ATP synthase (requires H+ gradient) and enzymes with Iron Sulphur clusters
Heat stable: reactions work faster at higher temperatures
Lipid membranes: required for chemical gradients
What characteristics would genes of LUCA possess?
Aleksandr Oparin and Alex Heldane (1920s)
Who was credited with the theory of the formation of life from chemistry?
That complex organic molecules can be created readily through simple chemistry
The Miller-Urey experiment proved what concept?
Compartments, metabolism and RNA for replication
What would primoridal soup require to become the first living cell?
Volcanic vents could provide compartments in the form of mineral pores
Could provide metabolism through ion gradients
Self-replicating RNA molecules evolved to be more efficient by imperfect replication
What could have provided the things needed for primordial soup to become the first living cell? How?
RNA molecules that behave like enzymes, catalysing and speeding up reactions
What are ribozymes?
A hydrogen ion gradient
What does ATP synthase require in order to work?
Cells made of DNA and proteins packaged inside lipids (fatty compounds meant to mimic the cell membrane). Not alive, but DNA contains instructions to replicate under the right conditions. By changing the pH of the sphere's enviroment, the researchers were able to trigger the cells to divide. In order to replenish the sphere's supplies, the researches combined the newly split cells with other cell-like structures. This worked, and the spheres had three successful generations
What are synthetic protocells?
-Water
-UV light and lightening (formation of polymers)
-Concentration of products
-Metal ions (catalyst)
-Compartments
-Concentration gradients (H+)
-Stable environment
What conditions could allow molecules to become 'life'?
Unlikely:
-too big, not concentrated enough
-no obvious compartments (seabed potentially)
-no UV light at depths
-low metal ions
-stable
-lots of water
How likely is it that 'life' could have formed in the ocean?
Possible (but unlikely):
-more UV light than in ocean
-concentration of products in rock pools
-water
-no compartments
-low metal ions
-no concentration gradient
-less stable than ocean
How likely is it that 'life' could've formed in shallow sea?
4.5 billion years
How old is the Earth estimated to be?
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