Biochem 2EE3 summary notes
Origin of Life
Prebiotic Era
- Certain Biochemical features common to all organisms
- Earth formation around 4.6 billion years ago
- Earliest fossils around 3.5 billion years ago
- Means prebiotic era was approximately 1.1 billion years long (time from
formation till first fossils)
Evidence for early life
- large mats containing stromatilides (sediments intermixed with microbes)
- individual fossils
Miller and Urey experiment
- gas mixture of what at the time was thought to be the composition of
the primodial atmosphere
- water and electric sparks were added
- amino acids were produced along with traces of other organic compounds
Elemental Composition of the Human Body
- mainly carbon, then N, O and H
- many trace elements (metals), all of which are essential for many
metabolic functions
Seawater compared to Extra-cellular fluid
- Na+ and Cl- are highest in both
- Exact molar amounts are different, but similarities do exist, such as the
ratio in which molarities appear
oSupports that life originated in oceanic water, most likely in a pool of
it on a beach
Polymerization
- how macromolecules appeared (protons and nucleic acids)
- simple molecules combine end to end and form polymers
- Complementarity between specific pairs of monomers
oAnion is complementary to H-bond donor
oDon’t need catalyst, it is not essential, there was all the time in
the world
Over time stable molecules remain, and make more copies of themselves
- natural selection favors certain types of self replicating macromolecules
- at some point, certain macromolecules were sequestered by a shell of
something
oneeded 1.1 billion years, likely faster as in the early stages of earth
the environment was inhospitable for any sort of molecule
