
Edit: @1:06 it says "Energy" a better word should have been "strength".
Sources:
Ch 2: Acids and Bases, Ch 22: The Organic Chemistry of Amino
Acids, Peptides, and Proteins (7th ed.) Bruice, Paula Y. Organic Chemistry
Ch 16: Acids and Bases (4th ed.) Tro, Nivaldo J. Chemistry: A molecular approach
Ch 13.3: Protein Structure - University of Kentucky Chemistry for Allied health