Systems Microbiolo46

Systems Microbiolo46 - This early atmosphere had mildly...

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Systems Microbiology • Life on Earth: How did we (everything) get here? (Lessons in geobiological engineering). o Microbes seem to have originated about 3.8 billion years ago. o But it turns out that the oldest rocks on Earth are only about 4 billion years old (existing in Greenland, Australia, and South Africa). o Slide: “The Early Earth System,” “The Evidence” o It’s hard to make all these inferences, because the earth looks so different now ° The early earth had no oxygen, water only as steam, and lots of asteroid collisions. o The origin of life on Earth: ° In situ (originating here) or panspermia (coming from elsewhere via a collision) • Panspermia seems unlikely, though interesting, because outer space can destroy these organic molecules very quickly. ° The Oparin ocean scenario, or hydrothermal vents? o Determining the atmospheric composition of the early earth is still largely guesswork
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Unformatted text preview: This early atmosphere had mildly reducing conditions As the earth cooled, H 2 0 dropped from the sky, and the oceans formed. These early oceans contained lots of sulfates and acids. Some scenarios for the origin of life: o The Miller Urey experiment: CH 4 , H 2 , NH 4 , and H 2 O, plus energy, will generate amino acids and simple sugars. o But how do you produce molecules that actually replicate? Slide: ribosomal RNA its folding, tertiary structure allows it to act as an enzyme: ribozyme. Thus we have a single molecule that can reproduce itself and act as an enzyme, and hence this might be where life originated Theres also a clay that can create lipids, and once one of these ribozymes ended up inside one of these lipid vesicles, very interesting things could happen. However, there are some problems we dont really know this is all speculative....
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This note was uploaded on 01/24/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.

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