A protein molecule in its folded native state has one favored conformation, but when it is denatured it becomes a random coil, with very many possible conformations.

Question

What must be the sign of the change in entropy (S) for the change native---> denatured

Would this be positive, since the protein is becoming more disordered?

Will the contribution of the change in S to the free energy change be positive or negative?

Would this be negative since a negative change in G indicates a spontaneous reaction, hence more disorder?

What requirement does this impose if proteins are to be stable structures?

I'm not sure about this answer

Answer 1

I think your answer to #1 is correct.
I think your answer to #2 is correct but I don't necessarily agree with your wording. I think the delta S indicates a more negative free energy; I don't know that I agree with the reverse of that.
I think the answer to #3 is that the protein must not be denatured (must remain in its native state).