MCB 2007 September 7th Lecture Notes

MCB 2007 September 7th Lecture Notes - September 7th...

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September 7 th Lecture Notes: The Basic Processes of Life: NASA Definition of life: “A self-sustained chemical system capable of undergoing Darwinian evolution.” Evidence of Life and Life Processes: life has to be able to reproduce itself and is based on a sequence of coordinated chemical reactions that manage life processes 1) Water: its unique properties are crucial to life. these include its lower density in solid form (expands when it freezes), high surface tension due to hydrogen bonding, and its high heat capacity. It also forms a seemingly infinite amount of configurations in solution. 2) Energy: the chemical composition of the Earth’s crust and organisms is incredibly divergent (Hydrogen most common element in organisms, oxygen in Earth’s crust) and is thus in a constant state of disequilibrium. A lot of energy is needed to maintain this imbalance. 3) Carbon-based molecules: large, carbon-based molecules comprise 26% of a cell, which is 87% of its overall dry weight (70% water remember). Organic molecules are based on carbon. A carbon atom’s four valences and relatively small nucleus give it tremendous versatility. Carbon can form chiral stereoisomers. Each molecule has its own stereospecificity, which is important in life processes. *Enzymatic activity is used in the synthesis of macromolecules (Each
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This note was uploaded on 05/11/2008 for the course BI 304 taught by Professor Oconnorandburgess during the Spring '08 term at BC.

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MCB 2007 September 7th Lecture Notes - September 7th...

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