Harrison W. answered 04/19/20
MCAT Expert, Weill Cornell Medical Student, 100th percentile MCAT
Hey Paige. Thanks for your question.
Peptide bonds are formed by joining two amino acids together. One amino acid "uses" its NH3 group to create the bond, and the other "uses" its COOH group to create the bond. In the process, water condenses and leaves (dehydration synthesis) and the peptide bond is formed.
Hope this helps!