Origins Flashcards
Did RNA come about before DNA?
Yes
Later on, throughout evolutionary time, what did DNA take over as?
heritable genetic material
What are the two current “origins of life” theories?
- intelligent design
- evolution (by natural selection)
What shaped the early earth atmosphere?
volcanic eruptions
What were the 3 main constituents of the early atmosphere?
- loads of UV light
- no ozone
- more water vapour
The RNA world (early atmosphere) was said to be…?
… a volatile place
What did Stanley Miller’s volcanic spark discharge experiment reveal? (2 answers)
- abiotic synthesis of amino acids
- Darwin’s “warm little pond” feasible
What is the RNA world hypothesis? (2 pathways)
- amino acid + amines–> catalyst–>RNA–>self-replicating system
- amino acid + amines–>instructions–>RNA–>self-replicating system
What are the RNA nucleic acid precursors created from? (3 answers)
- HCN (hydrogen cyanide)
- H2S (hydrogen sulphide)
- UV light
How does RNA act as instructions?
- complementary base pairing enables a single RNA strand to serve as a template for an exact copy
What are the pairings in RNA?
- A and U
- C and G
How does RNA act as a catalyst?
- base pairing and H-bonding; RNA folds into 3D shapes
- determined by nucleotide sequence
What does the folding of RNA permit?
production of ribozymes
When RNA acts as an enzyme, what does the simple structure limit?
- catalytic efficiency and slope
What is ribose formed from?
formaldehyde
