BIO 1 Origin of Life - BIO153: Lecture 1 Origins of Life...

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1 BIO153: Lecture 1 Origins of Life January 5 th , 2009 Life on earth is diverse… where did it all come from??? In the beginning. .... origin of universe: ~ 13.7 billion years ago earth formed ~ 4.5 billion years ago life arose from non-life ~ 4.4 billion years ago (perhaps) What is life? “I am not going to answer this question .” — J. B. S. Haldane Life is cellular: cells are enclosed by an osmotic barrier (cell membrane) cells have internal reactions catalyzed by proteins within cells, there occur the formation/hydrolysis of P –bonds in energy-transforming reactions cells have a conservative biochemistry (all cells use a limited repertoire of biochemical reactions and components) Cells show all the characteristics of life: 1. Cells are highly structured - diverse, but similar b i o c h e m i s t r y 2. Cells metabolize - transform energy, possess metabolic pathways, process nutrients 3. Cells self-regulate - adjust to environment, osmoregulate, communicate
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2 4. Cells reproduce - grow, divide and differentiate 5. Cells can evolve - replication is not perfect; variations subject to selection What about viruses? not cellular no metabolism: no ATP, respiration, fermentation, photosynthesis no growth or division tiny (thousands can fit in an average bacterium!) obligate intracellular parasites replicate by “hijacking” host DNA/RNA recently implicated in cancer not primitive - multiple origins; host genomes … and prions? infectious agent made entirely of protein
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This note was uploaded on 04/25/2010 for the course BIOLOGY BIO153 taught by Professor Cordon during the Fall '10 term at University of Toronto- Toronto.

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BIO 1 Origin of Life - BIO153: Lecture 1 Origins of Life...

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