Emergent Life II
A Proposed Origin Of Life On Earth:
from protobionts to living cells
adapted from Biology, 2015, tenth edition, pp. 439-446
an internal energy source is
to form a
AN RNA WORLD:
"...the first informational molecule to evolve in the progression toward a self-sustaining, self-reproducing cell...proteins and DNA...came...later...[is] self-replicating RNA molecules...[that] functioned as both enzymes and substrates for their own replication...", eventually catalyzing and facilitating peptide bond formation, and also eventually making double-stranded copies of itself (i.e., DNA) (Biology 2015, 10th edition, p. 442, 443).
of organic polymers
promote the development of:
1) surface membranes of fatty acids and monoglycerides,
surrounding larger DNA-like molecules;
2) small, organic molecules, or nutrients, that can enter (diffuse) through the cell membrane;
3) larger DNA molecules that cannot leave the cell; and,
4) DNA, that with its double helix structure, is more stable/less reactive, than RNA.