Energy, Catalysis and Biosynthesis Metabolism *catabolism *anabolism Complexity of metabolism *potential energy

Conservation of Energy Energy is defined as the capacity to perform work. Kinetic energy is the energy of motion. Potential energy is stored energy.

Free energy, stability, and change Free energy Change in free energy =  G Gravitational Motion DiffusionChemical Reaction

Equilibrium *chemical equilibrium  G = 0, no net change in the system Chemical reactions with free energy changes: *energetically favorable *energetically unfavorable Free energy, stability, and change

Metabolic Disequilibrium *Multistep open hydroelectric system

Enzymes – Metabolism is the total of all chemical reactions in an organism. – Most metabolic reactions require the assistance of enzymes, proteins that speed up chemical reactions.

Activation Energy Reactant Products Activation energy barrier Energy level – Activation energy Activates the reactants Triggers a chemical reaction

Enzymes lower the barrier of E A Enzymes (b) With enzyme Reactant Products Activation energy barrier reduced by enzyme Enzyme Energy level

ATP and Cellular Work Main types of (cellular) work: mechanical transport chemical

The Structure of ATP TriphosphateDiphosphate Adenosine Energy ATPADP PPPPPP Phosphate (transferred to another molecule) – ATP (adenosine triphosphate) Consists of adenosine plus a tail of three phosphate groups Is broken down to ADP and a phosphate group, releasing energy

The Structure of ATP

ATP ADP P P P P P P P P X XY Y (a) Motor protein performing mechanical work (b) Transport protein performing transport work (c) Chemical reactants performing chemical work Solute Solute transported Protein moved Product madeReactants Transport protein Motor protein ATP and Cellular Work

Redox reaction (oxidation-reduction) Na + Cl Na + + Cl - oxidation reduction Xe - + Y X + Ye - oxidation reduction ATP and Cellular Work

NAD+ (another activated carrier)