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Unformatted text preview: 1 Chapter 8: And Introduction to Metabolism Important Point: Metabolism (Overview) ¡ Metabolism = Catabolism + Anabolism ¡ Catabolic reactions are energy yielding ¡ They are involved in the breakdown of more-complex molecules into simpler ones ¡ Anabolic reactions are energy requiring ¡ They are involved in the building up of simpler molecules into more-complex ones ¡ We can consider these bioenergetics in terms of the physical laws of thermodynamics 1 st & 2 nd Laws of Thermodynamics “Energy can be transferred or transformed but neither created nor destroyed.” p. 143, Campbell & Reece (2005) “Every energy transfer or transformation increases the disorder (entropy) of the universe.” p. 143, Campbell & Reece (2005) Note especially the waste heat Organisms are Energy Transducers ¡ Organisms take in energy & transduce it to new forms (1st law) ¡ As energy transducers organisms are <100% efficient (2nd law) ¡ Organisms employ this energy to: • Grow • Protect Themselves • Repair Themselves • Compete with other Organisms • Make new Organisms (I.e., babies) ¡ In the process, organisms generate waste chemicals & heat ¡ Organisms create local regions of order at the expense of the total energy found in the Universe!!! We are Energy Parasites! Water “Fall”Analogy Get it? 2 Laws of Thermodynamcs ¡ First Law of Thermodynamics: • Energy can be neither created nor destroyed • Therefore, energy “generated” in any system is energy that has been transformed from one state to another (e.g., chemically stored energy transformed to heat) ¡ Second Law of Thermodynamics: • Efficiencies of energy transformation never equal 100% • Therefore, all processes lose energy , typically as heat, and are not reversible unless the system is open & the lost energy is resupplied from the environment • Conversion to heat is the ultimate fate of chemical energy Movements Toward Equilibrium...
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This note was uploaded on 06/03/2011 for the course BIO 113 taught by Professor Swenson during the Spring '08 term at Ohio State.
- Spring '08