Lecture 4- Origin of Life Flashcards
What are the four steps of abiogenesis?
Abiotic synthesis of monomers → synthesis of macromolecules → formation of protocells → appearance of self-replication
What conditions must be met to facilitate the abiotic synthesis of monomers?
Little or no free oxygen, source of energy, time for molecules to react, & presence of biochemical building blocks (CHON)
Where did life initially form according to the Prebiotic Soup Hypothesis?
Life formed near earth’s surface
Where did life initially form according to the Iron-Sulfur World Hypothesis?
Life formed at cracks of the ocean floor in hydrothermal vents
What was the significance of the Miller-Urey experiment in 1953?
Tested prebiotic soup hypothesis → formed amino acids and other organic molecules (provided first evidence that organic molecules could be synthesized from inorganic compounds)
True or false: The first living prokaryotes were photosynthetic autotrophs
False; the first living prokaryotes were anaerobic heterotrophs which used fermentation
Why did prokaryotic cells evolve from anaerobic to aerobic?
Use of oxygen allows for more ATP production
Why is it important for there to be minimal free oxygen during the abiotic synthesis of monomers?
Ample free oxygen would break bonds (oxidation) and inhibit monomer formation
How do protocells differ from self-replicating cells?
Protocells exhibit some attributes of living cells but lack a mechanism for heredity
What was the significance of the emergence of photosynthetic autotrophs?
Released oxygen into atmosphere → 99.9% of creatures went extinct
