Section 2-1 Origin of life Flashcards
How long ago was the earth formed?
4.6 Billion years ago.
What elements were in the primitive atmosphere?
CH4, NH3, CO2, N2, H2, H20.
What was most likely the first living organism?
A prokaryote.
What is a prokaryote?
A cell lacking membrane bound organelles.
Earliest prokaryotes were found in stromatolites. What are stromatolites?
Dome shaped sedimentary rocks found in Australia, Southern Africa and northern Canada.
Some Stromatolites are 3.5 billion years old.
Some Stromatolites are 3.5 billion years old.
What defines a cell?
Metabolism: producing and consuming energy.
Reproduction: all cells arise from previous cells.
What are complex organic molecules composed of?
Protein, Carbohydrates, lipids, nucleic acids (DNA, RNA)
What is the difference between Dehydration Synthesis and Hydrolysis?
Dehydration Synthesis turns monomers into polymers.
Hydrolysis turns polymers into monomers.
What are the 3 Evolutionary crossroads?
- Origin of life
- Origin of eukaryotes
- Origin of multicellularity
What was the sequence in which life originated?
- Abiotic synthesis of small organic molecules
- Joining of these small molecules into macromolecules,
- Packing of molecules into “protobionts”.
- Origin of self-replicating molecules.
What are the names of the two Scientists who did experiments to show that abiotic synthesis could occur in the reducing atmosphere?
Alexander Oparin and
J.B.S Haldane
What was the problem with Oparin and Haldane’s experiment?
The existence of such a reducing atmosphere that would support abiotic synthesis is unlikely.
Where might Abiotic Synthesis have occurred if not in a reducing atmosphere?
Near submerged volcanoes and deep-sea vents.
How were polymers formed?
Through the addition of a solution to clay and iron pyrite.
Protobionts/protocells exhibit reproduction and metabolism. Where are they formed?
Formed in abiotically produced vesicles. (Adding clay to can increase the rate of vesicle formation).
Modern cells go through the process of DNA -> RNA -> Proteins. What sequence did the 1st genes go through?
RNA molecules probably polymerized abiotically which allowed them to self-replicate.
