Figure 5-13 Phospholipids can form micelles like FA's, but they also form bilayers V . R-Group varies with different aa's. 20 different R-groups differentiate the 20 different common aa's, the aa's found in proteins. This is called a Zwitterion. These are two possible sterioisomers of an amino acid.
Proteins contain only L-isomers of amino acids .
See Figure 5.15 of Text for structures of amino acids and classification by properties of their R-groups. Figure 5-16 1. The 2nd bond in a double bond is a p -bond formed between p atomic orbitals. The bilobed structure of p orbitals prevents rotation about -bonds. 3. Here each planar peptide group is represented by a rectangle connected to a -C's at its vertices.