Introduction to Energy and Life PDF

Introduction to Energy and Life  Energy Is Central to Life All living things require energy. The sun is the ultimate source of energy for most living things, but not all... photosynthesis chemosynthesis  Energy Conversions ❑ ~1% of Sun’s E – captured by plants...

Introduction to Energy and Life  Energy Is Central to Life All living things require energy. The sun is the ultimate source of energy for most living things, but not all... photosynthesis chemosynthesis  Energy Conversions ❑ ~1% of Sun’s E – captured by plants ❑ ~30 reflected back into space ❑ ~70% absorbed by land, oceans, atmosphere - most transformed into heat.  Where does E from the sun come from? Nuclear Fusion w/in sun’s core 1) Convert H → He 2) Convert mass to E P + P N Hydrogen Deuterium E=0 E=3 fusion P N Helium E=2 P  Energy Conversions Life depends on E from the sun that is converted into usable forms for life. Photosynthesis Cellular respiration  Yeast, bacteria, O2- starved muscle cells ethyl alcohol  What is Energy? The capacity to do work Work = Moving matter against an opposing force Think: passive vs. active transport?  Energy has two forms Potential Kinetic Stored E E of motion (also heat, light)  Thermodynamics Thermodynamics: The study of energy Laws of Thermodynamics: fundamental principles of energy.  1st Law of Thermodynamics Conservation of Energy Energy is never created or destroyed but is only transformed E of an isolated system is constant  2nd Law of Thermodynamics Law of Entropy ▪ Energy transfer will always result in a greater amount of disorder in the universe. ▪ Entropy is always increasing in universe Order → Chaos Energy Is Central to Life E flows through ecosystems in 1 direction ~10% E 90% lost as ~10% heat 2 °Consumers 1 ° Consumers ~10% E transfer 1 ° Producers  E conversions are imperfect - Always Pay E Tax! Some E always lost as heat Heat = least usable form of kinetic E ~75% of E in gas is lost as heat  Endergonic vs. Exergonic Rxns  Endergonic – Requires E "within" "work" Absorbing energy Not spontaneous Product monomer + monomer + Energy Polymer  Endergonic Rxns Linkage of simple sugars → complex carbohydrate = endergonic Such a reaction will not occur without an input of energy. +E  Exergonic – Release E "outside" "work" Releases energy ‘eager’ Energy Product monomer + monomer Polymer  Exergonic Rxns Breakdown of complex carbohydrate → simple sugars = exergonic Such a reaction releases energy. E Metabolism: Catabolic vs. Anabolic Break things apart Build things