Define and compare the four levels of protein organization.

What are the two common types of protein secondary structure, and how do they differ?

How do covalent disulfide bonds, hydrogen bonds with water, and hydrophobic interactions all contribute to a protein's tertiary structure?

List as many different categories of protein functions as you can. Wherever possible, give an example of each category.

How does an enzyme function? Why are enzymes essential for living organisms on Earth?

Exon shuffling is a proposal that relates exons in DNA to the repositioning of functional domains in proteins. What evidence exists in support of exon shuffling?