AAMC C/P Practice Test 2026 FL 3 – All-in-One Guide to Mastering Chemical & Physical Foundations of Biological Systems!

The correct expression for ΔG′° in terms of the concentrations of the native and unfolded states during a denaturation process reflects how the Gibbs free energy change relates to the favorability of the native state compared to the unfolded state.

The standard free energy change (ΔG′°) is given by the equation:

\[

ΔG = ΔG'° + RT \ln Q

\]

where \( Q \) is the reaction quotient, defined as the ratio of the concentrations of products to reactants. In the context of protein denaturation, when considering native and unfolded states, we denote the native state as the more stable state that corresponds to a lower Gibbs free energy.

In this context, the equilibrium expression for the denaturation process can be formulated as:

\[

Q = \frac{[\text{unfolded}]}{[\text{native}]}

\]

The relationship between ΔG′° and the concentrations of the native and unfolded states becomes:

\[

ΔG'° = -RT \ln Q = -RT \ln \left(\frac{[\text{unfolded}]}{[\text{native}]}\right)

\]

This formulation indicates that when native states are favored (when they are