Chapter 4

Explain how the $\mathrm{p}{K}_{\mathrm{a}}$ of an amino acid can differ within a folded protein compared to that of the free amino acid in water.

What is a peptide bond and how is it formed?

Name and briefly describe the four levels of protein structure.

Explain how an $\alpha$ helix can be amphipathic.

Explain why secondary structures are so prevalent in proteins.

What are three ways in which quaternary structures can provide increased functionality for a protein?

What is thought to be the dominant mechanism of protein folding? Why can it not be random?

What are the enthalpic and entropic factors that lead to the stabilization of a protein upon protein folding?

Name and briefly describe the three proposed mechanisms of how globular proteins fold in aqueous environments.