ΔG_fold = ΔH − T·ΔS
Denaturation: T↑ or pH extreme → ΔG > 0 → unfold
Biomolecules are polymers of simple monomers: amino acids (protein), monosaccharides (carbs), fatty-acid chains (lipids) and nucleotides (DNA/RNA). Folded 3D shape is set by a free-energy balance of hydrogen bonds, hydrophobic packing and electrostatics — push temperature or pH too far and the chain denatures.
- Molecule type — switches between a folding protein helix, a branched carbohydrate chain, a lipid bilayer patch, and a DNA double helix.
- Temperature — heat disrupts hydrogen bonds; past ~60°C most proteins denature (unfold).
- pH — extreme acid/base shifts side-chain charges, also destabilising the folded structure.
- Chain Length — number of monomer units rendered in the polymer.
Real-world use: this folding/denaturation trade-off is why cooking an egg (heat) or curdling milk with lemon juice (pH) both permanently unfold proteins.