University:
North Seattle College
Course:
CHEM 255 | Biochemistry I
Academic year:

2023
Views:

18

Pages:

4
Author:

Christopher Brooks

Free Energy of the energy actually available to do work (utilizable) is known as free energy • Changes in free energy (AG) are the feasibility of chemical valuable in predicting reactions. 7 Dweing or a absorbed. chemical heat may be released •7 The randomly disperered energy is called Entropy (as) disorder • It represents a in the gandomness or change in of reactants & products. As change • Entropy attains a maximum equilibrium. as the on approaches Stre The reactions of biological systems involve a temporary decrease in entropy + > The relation between the changes of free energy (sa) Enthalpy (AH) and Entropy (46) is ( As the volume Change ΔΗ – TAS AG expressed as biochemical reach used of The term standard free energy (4G") is often use to indicate free enougy change when the reactants or The products are at a conc of I mol / let at pH 7.0 In 1878, Gibbs created the free energy function by combining the first & second lace energy of thermodynamics AG = AH-TAS Example enengy carry out oxidation change in free energy of a reacting system change is heat content Enthalpy of ΔΗ - To know the mang nikte of changes Aerobic oxidation T- Absolute tempested. AS- change in Entropy of Living Cell. at The Enthalpy change, 44 is tamp geven by = ΔΕ + PAV+64 Ass cong ci Kat the Temp 2 change in internal energy of 1.0 atm (760 mm Haf) which aa reactiond conditions AV - calculations. change, As the Volume Et change in volume AV IS small of the me of for nearly waction biochemical 680,000 eq modefees as follocos reactions of ecce. 613 000 > Thus change in free energy of a sixn, (4G) depends both on the change in internal energy and on change in Entropy of the system. CLS the T AG is a valuable criterios in determining whether a reaction can оссия spontaneously 4-4 cal/day > of AG is negative, the sixn proceeds spontaneously with loss of free energy is it 16 Enengonic If AG is positewe, the rxn proceeds only of free energy can be gained ie it is Endergonic > If AG is zero Enample yxn system is at equilibrian To know the mangnitube of changes in various forms of energy, Aerobic oxidation of glucose may be cited. Living Celli carry out oxidation of glucose in the presence of O₂ to co₂ * H₂O at Const temp & pressure Con C6H206 + 602 → 6CO₂ + 6H₂O cone of en Assuring that the temp is 25°C (298k) and the pressua à 1.0 atm (760 mm Hg) which are standard conditions in thermo dynamic calculations, the following energy changes take place per molecule of glucose oxidued AG = -686,000 cal mol = -673,000 callmd Eq may also be weutter as 48-44-44; -673,000-(-686,000) AS = 298 = 44 Cal/deg