This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Class Notes 10/17/07 Review from last time:-Maybe not the oceans because of the problems with polymerization and no enzymes maybe it was the hydrothermal vents 2) Amino Acid Polymerization (ctd)-Sidney Fox: conducted research at Florida State then went to U Alabama at Mobile and retired today he clearly demonstrated how amino acids could be spontaneously polymerized under hot dry conditions such as rocks that existed near a volcano maybe on a hot, rocky beach. He did this in a laboratory.-He mixed up dilute solutions of amino acids, then took the solution of monomer molecules and dripped it onto hot surfaces-He used hot sand, hot clay, hot rock, and what happens when it drips onto the surface is that the heat will vaporize the water, leaving the monomer material concentrated on the hot surface the monomers were chemically binding (some of them) to particles like iron and zinc that were composed in that clay-like material.-Ex. Hot fire that sizzles when you spit it in-The only way spontaneous polymerization occurs if the concentration of monomers is high compared to the hot surface concentration then the potential is there-So if some volcano broke surface of an ocean the waves splashed onto the hot magma/steam, the foamy material washes up onto hot rock, water vaporizes, monomer material concentrates on the hot rock, then next time a wave comes up, the material may wash back into ocean as polymers.-Fox produced chains of amino acids that were over 200 units in length (polypeptides)-He named them thermal proteinoids-When you took the heated mixture of polypeptides, and plunged it quickly into water, those thermal proteinoids would cluster, or aggregate into a mass in that water medium. As he analyzed the mass, he found that it had a bi-layered surface area kind of like a membrane.-He called these bi-layered units proteinoid microspheres .-Polymers of nucleotides, DNA, RNA, have been synthesized in labs in a similar fashion as Foxs proteinoids. Scientists actually create these molecules that form life. 3) Formation of Protobionts Protobionts -In order for the first cell to appear, people suggest it wasnt a direct step from polymers to prokaryotes it may have involved the organic matter clustering together (protobionts) these are spontaneously created aggregates named protobionts-They have interesting characteristics: resemble living cells:-They cant precisely reproduce because there are no replicator molecules like RNA/DNA -They can maintain a reasonably controlled internal environment-Most can carry out some level of metabolism-They have a degree of excitability or irritability (respond to an environmental stimulus)-Just like our nervous system characteristics we flinch with pain-Amoeba under microscope take an eye dropper with acetic acid, as amoeba sense acid coming closer, pseudopods form away from medium so it begins to move...
View Full Document