Cells - Download 4 Download Cells the units of life Principles of Biology BIOL 1543 Greig Roberts DDS Office SCEN 417 E-Mail [email protected] The

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Download 4 Download 4 Cells – the units of life Principles of Biology BIOL 1543 Greig Roberts, DDS Office: SCEN 417 E-Mail: [email protected]
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2 The Art of Looking at Cells Early scientists who observed cells made detailed sketches of what they saw These early sketches revealed an important relationship between art and biology, the most visual of the sciences
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3 Life began on a young Earth Planet Earth formed some 4.6 billion years ago Fossilized prokaryotes called stromatolites date back 3.5 billion years The early atmosphere probably contained H 2 O, CO, CO 2 , N 2 , and some CH 4 Volcanic activity, lightning, and UV radiation were intense
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4 How did life form? Simulations of Earth’s early conditions have produced amino acids, sugars, lipids, and the nitrogenous bases found in DNA and RNA. Cooled water containing organic molecules Cold water Condenser Sample for chemical analysis H 2 O “Sea” Water vapor “Atmosphere” Electrode CH 4 N H 3 2
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5 Other critical steps Organic polymers such as proteins and nucleic acids may have formed on hot rocks or clay. The first genetic material and enzymes may both have been RNA. G A G G C G G G C C C A A A A U U U U G C U A U G C A U U C G G U U U G C A U A U G C A 1 2 Formation of short RNA polymers: simple “genes” Assembly of a complementary RNA chain, the first step in replication of the original “gene” Monomers
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Additional critical steps Membranes may have separated various aggregates of self-replicating molecules (RNA and polypeptides), which could then be acted on by natural selection. LM 650
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This note was uploaded on 10/14/2011 for the course BIOL 1543 taught by Professor Roberts during the Spring '08 term at Arkansas.

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Cells - Download 4 Download Cells the units of life Principles of Biology BIOL 1543 Greig Roberts DDS Office SCEN 417 E-Mail [email protected] The

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