Bio Exam 3 review sheet

Bio Exam 3 review sheet - 1 a Catabolism release the energy...

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1. a) Catabolism- release the energy stored in complex molecules through the breakin down of these molecules into simpler compounds; decrease in free energy -^G; exergonic-spontaneous. b) Anabolism-biosynthetic pathway- require energy to combine simpler molecules into more complicated ones; increase in free energy +^G; endergonic- non-spontaneous. 2. 1 st Law of thermodynamics- energy can be neither created nor destroyed. 2 nd Law of thermodynamics- every energy transformation or transfer results in an increasing disorder within the universe. 3. Entropy (S) is used as a measure of disorder or randomness. A spontaneous process, without the input of external energy, must result in an increase in entropy; A non-spontaneous process will occur only if energy is added to the system Enthalpy (H) is the toal energy of a sstyem. 4. free energy, ^G, is the portion of a system’s energy available to perform work when the system’s temperature and pressure are uniform. ^G = ^H – T(^S) free energy=total energy- abs tempxentropy For a reaction to be spontaneous, the free energy of the system must decrease (- ^G): the system must lose energy (H must decrease), become more disordered (S must increase), or both. 5. p. 1197. Carbon cycle- Nitrogen cycle- a) Nitrification- NH4+ is converted to NO3- by nitrifying bacteria b) Ammonification- decomposes organic nitrogen to NH4+ c) Denitrification- under anaerobic conditions, denitrifying bacteria use NO3- in their metabolism instead of O2, releasing N2. 6. 7. 8. 9. ATP = adenosine triphosphate – nitrogenous base adenine + sugar ribose + 3 phosphate groups…… a) Mechanical work: ATP phosphorylates motor proteins b) Transport work: ATP phosphorylates transport proteins c) Chemical work: ATP phosphorylates key reactants 10. energy coupling- using exergonic processes to power endergonic ones. …….In coupled reactions, energy released by hydrolyzing ATP drives the conversion of substrates to products. 11. enzymes- cataliysts, agents that speed the rate of a reaction but are unchanged by the reaction. 12. 13. activation energy=the extra energy required to destabilize existing chemical bonds and initiate a chemical reaction. = free energy of activation, EA, is the initial energy that must be absorbed by reactants to reach the unstable transition state, in which bonds are likely to break, and from which the reaction can proceed. 14. a) Rise in temperature- the velocity of an enzyme-catalyzed reaction may increase w/ rising
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This note was uploaded on 09/01/2009 for the course BIO 311C taught by Professor Satasivian during the Fall '08 term at University of Texas.

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Bio Exam 3 review sheet - 1 a Catabolism release the energy...

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