Evolution test 3

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Evolution test 3
2013-11-06 01:32:32
Evolution ccraigr

test 3
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  1. What is the LUCA
    Last Universal Common Ancestor
  2. How does the possibility of an RNA world help explain how life originated on earth?
    The RNA World hypothesis proposes that catalytic RNA molecules were a transitional form between nonliving matter and the earliest cells.
  3. What are two major problems with the RNA world hypothesis?
    • 1. catalytic RNA cannot yet replicate themselves.
    • 2. It synthesized new RNA strands slower than it decomposes.
  4. What is the current conclusion regarding RNA and the origin of life?
    • 1. Information containing biomolecules need to be made
    • from simple inorganic compounds.
    • 2. The chemical reactions that construct
    • larger molecules from simple inorganics must be favorable and have a source of
    • energy.
    • 3. The building blocks must be able to self-assemble into polymers such
    • as RNA and polypeptides.
    • 4. Larger biomolecules must be protected from harsh
    • environmental conditions.
  5. What did we learn from the Murchison Meteorite?
    • The simple amino acids may have formed in space and
    • then entered earth as meteorites or cosmic dust.
  6. What is the panspermia hypthesis?
    It is the hypothesis surrounding the extraterrestrial origin of life.
  7. What was Miller’s experiment and why have the result been questioned?
    • He produced the starting blocks of life (organic molecules) abiotically.
    • Now we think that the atmosphere of early earth was not as reducing as Miller thought.
  8. Describe the Oparian-Haldane model
    • The primordeal soup from which life sprang.
    • 1. Assembly of simple molecules.
    • 2. Assembly of polymers that can store information and catalyze reactions.
    • 3. The additions of membranes and energy sources for living organisms.