Thermodynamics and Metabolism

1. Thermodynamics and Metabolism A. Thermodynamic Quantities • _____________change(___) is a measure of the _______________ _______________fromareaction • ___ = change in ______________ • ___ = change in ______________

2. Both entropy and enthalpy contribute to DG • (T = degrees Kelvin) • ____ = reaction is _____________ in the direction written • ______ = reaction is ______________ • _________ reaction is at ___________ Relationship among energy, enthalpy and entropy

3. The Standard State (DGo) Conditions • Reaction free-energy depends upon conditions • ________________(_____)- defined reference conditions • Standard Temperature = ______(25oC) • Standard Pressure = ______________ • Standard Solute Concentration = _____ • ____________standard state = _____ • Standard ____ concentration = _____ • (________) rather than 1.0M (pH = 1.0)

4. B. Equilibrium Constants and Standard Free-Energy Change • For the reaction: _______________ • At equilibrium: • And _________________, so that:

5. C. Actual Free-Energy Change Determines Spontaneity of Cellular Reactions • When a reaction is not at equilibrium, the _______________ _____________________________ _____________________________ (the ratio) • ____ = the _______________ ratio Where

6. The Free Energy of ATP • ___________________ of metabolic fuels is largely _________________ ______________________________

7. ATP is an “______________”compound • A large amount of energy is released in the hydrolysis of the _______________________ of ATP (and UTP, GTP, CTP) • All nucleoside phosphates have nearly equal standard free energies of hydrolysis

8. Complexes between ______and ______ Why are phosphoanhydrides high energy compounds? (1) ____________________ among negatively charged oxygens of phosphoanhydrides of ATP (2) ______________________ (ADP and Pi) or (AMP and PPi) is better than solvation of reactant ATP (3) ______________________thanreactants There are more delocalized electrons on ADP, Pi or AMP, PPi than on ATP

9. The Metabolic Roles of ATP • ______________________________________________________________________ • Reactions can be linked by a common _____________________ (B-X) below • A-X + B A + B-X • B-X + C B + C-X Glutamine synthesis requires ATP energy

10. Phosphoryl-Group Transfer • ___________________________ - the ability of a compound to ______________________ ____________________________________ • Energy-rich or high-energycompounds have group transfer potentials _________________ ____________________________________ • Low-energycompounds have group transfer potentials less than that of ATP

11. Production of ATP by Phosphoryl-Group Transfer • ___________________________________ ___________________________________ to form ATP • __________________________________ in ________________ pathways • ___________________________________ ___________________________________ Relative phosphoryl-group-transfer potentials

12. Transfer of phosphoryl group from PEP to ADP • Phosphoenolpyruvate (PEP) (a glycolytic intermediate) has a high P-group transfer potential • PEP can donate a P to ADP to form ATP ___________________: Energy-rich storage molecules in animal muscle • _______________ (PC) and _____________ (PA) are ________________________ • Have higher group-transfer potentials than ATP • Produced in muscle during times of ample ATP • _____________________ when needed via creatine kinase reaction

13. Structures of PC and PA __________-Group Transfer • Transfer of the nucleotidyl group from ATP is another common group-transfer reaction • ___________________ requires transfer of an ________moiety to acetate • ___________________________________ ___________________________________

14. Synthesis of acetyl CoA

15. _________ Have High Free Energies of Hydrolysis • Thioesters are energy-rich compounds • _____________ has a DGo’ = -31 kJ mol-1 _____________ Energy Can Produce GTP

16. __________________________________ from Biological Oxidations • Amino acids, monosaccharides and lipids are oxidized in the catabolic pathways • ____________________________________ ____________________________________ • ___________________________________ • Oxidation of one molecule must be coupled with the reduction of another molecule • Ared + Box Aox + Bred Free-Energy Change Is Related to Reduction Potential • The ____________________ of a reducing agent is a measure of its thermodynamic ________________ • The __________________ is the measured __________________________________ • Reference half-cell reaction is for hydrogen: • 2H+ + 2e- H2

17. Diagram of an electrochemical cell • Electrons flow through external circuit from Zn electrode to the Cu electrode

19. Standard reduction potentials and free energy • Relationship between standard free-energy change and the standard reduction potential: n = # electrons transferred F = Faraday constant (96.48 kJ V-1) DEo’= Eo’electron acceptor - Eo’electron donor Actual reduction potentials (_____) • Under biological conditions, reactants are not present at standard concentrations of 1 M • Actual reduction potential (DE) is __________ _________________ of reactants and products

20. __________________________________________ _______________________________________ • Most _______ formed in metabolic reactions in aerobic cells is _____________________ ___________________________________ • Energy _________________ from ADP, Pi • Half-reaction for overall oxidation of NADH: Methods for Studying Metabolism • Add ______________ to tissues, cells, and follow emergence of intermediates • Use sensitive isotopic ______ (3H, 14C etc) • Verify pathway steps in vitro by using ____________________ and substrates • Use metabolic ____________ to identify individual steps and sequence of enzymes in a pathway