Biochemical Pathways: A Comparative Analysis of Energy Transfer inPhotosynthesis and Cellular RespirationEssay Questions:1.Define ΔG anddescribe how it relates to changes in entropy and enthalpy.HowΔG isrelated to the equilibrium constant of a reversible reaction and explain why cells maintainproduct/substrate concentrations below the equilibrium constant in metabolic pathways?Answer:ΔG (Gibbs free energy) represents the energy available to do work in asystem at constant temperature and pressure. It relates to changes in entropy (ΔS)and enthalpy (ΔH) by the equation:•ΔHis the change in enthalpy (heat content),•Tis the temperature in Kelvin,•ΔSis the change in entropy (disorder).If ΔG is negative, the reaction is spontaneous. If ΔG is positive, the reaction is non-spontaneous.Equilibrium and ΔG: At equilibrium, ΔG = 0. The relationship between ΔG and theequilibrium constant (K) is given by:where R is the gas constant and T is the temperature. A large K (favorable reaction)means a negative ΔG, and a small K means a positive ΔG.Cells maintain product/substrate concentrations below equilibriumto ensurereactions proceed in the direction that supplies energy (negative ΔG), preventingequilibrium from being reached and sustaining metabolic processes.Preview Mode
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