Name: Julian D.
Why is it now thought that proteins were not the first
macromolecules to form on Earth?
For something to be alive remember that it has to meet certain criteria
(characteristics of life). One of these is the ability to reproduce. If
proteins came first (by spontaneous chemical combinations that produced
something organic), how could it pass this information on to another
generation of life? So now one hypothesis says that RNA came first and was
capable of making copies of itself. Then DNA (double-stranded) evolved and
DNA was capable of passing on information for making proteins.
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Update: June 2012