MCAT Organic Chemistry Review 2018-2019

of the backbone of proteins. The single bonds on either side of the peptide bond, on the other hand,
permit free rotation.

Figure 10.5. Resonance  in  the Peptide Bond

KEY CONCEPT

Rotation    is  limited around  the peptide bond    because resonance   gives   the C–N bond    partial

double-bond character.

MCAT    Concept Check   10.1:

Before  you move    on, assess  your    understanding   of  the material    with    these   questions.

What    makes   glycine unique  among   the amino   acids?

Amino   acids   are amphoteric. What    does    this    mean?   What    functional  groups  give    amino

acids   this    characteristic?

How are peptide bonds   formed  and cleaved?