Chapter 14, Problem 14.29QP

Interpretation Introduction

Interpretation:

The free energy change associated with the denaturation of protein has to be calculated in accordance with the given conditions.

Concept introduction:

Thermodynamics is the branch of science that relates heat and energy in a system.  The four laws of thermodynamics explain the fundamental quantities such as temperature, energy and randomness in a system.  Entropy is the measure of randomness in a system.  For a spontaneous process there is always a positive change in entropy. Free energy (Gibbs free energy) is the term that is used to explain the total energy content in a thermodynamic system that can be converted into work.  The free energy is represented by the letter G.  All spontaneous process is associated with the decrease of free energy in the system.  The equation given below helps us to calculate the change in free energy in a system.

$\text{ΔG = }\Delta {\rm H}\text{- T}\Delta \text{S}$

where,

$\text{ΔG }$ is the change in free energy of the system

$\Delta {\rm H}$ is the change in enthalpy of the system

$\text{T}$ is the absolute value of the temperature

$\Delta \text{S}$ is the change in entropy in the system

Protein is a macromolecule made of many number of amino acids.  They are essential molecules in the biological system.  Denaturation of protein refers to the unfolding of the folded chain of protein.  The denaturation process can be initiated by heat energy.  The entropy of denaturation of protein is calculated by using the values of the change in enthalpy in a system and the temperature.

${\text{ΔS}}_{\text{denatuaration}}\text{=}\frac{{\text{ΔΗ}}_{\text{denaturation}}}{\text{T}}$