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Unformatted text preview: 1 Extraterrestrial Life: Spring 2008 Extraterrestrial Life: Lecture #9 Reminder: homework #2 due Thursday my ofFce hours after class today (tomorrow afternoon also good) Last class: radioactive dating of rocks Today: what are the characteristics of life on Earth, and how general are those properties? Reading: textbook Chapter 5 `The nature of life on Earth Extraterrestrial Life: Spring 2008 DeFnition of life Life is a self-sustaining chemical system capable of undergoing Darwinian evolution Very general deFnition: requires source of energy, and some hereditary `memory Single known example of life: involves a set of very speciFc molecules and reactions with limited variety When searching for life (e.g. on Mars) which aspects of life on Earth should we assume are likely to be general to life elsewhere? Extraterrestrial Life: Spring 2008 All life on Earth shares common features: Contained within cells Molecules called lipids form cell membranes that enclose the cell Cell membranes contain the chemical reactions within the cell Can form spontaneously when lipids are placed in contact with water Extraterrestrial Life: Spring 2008 Relies on proteins made from subset of amino acids Contains an amino group (NH 2 ) and a COOH group Proteins make up both the...
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This note was uploaded on 08/31/2009 for the course GEOL 3300 taught by Professor Staff during the Spring '08 term at Colorado.
- Spring '08