Self And The Phenomenon Of Life: A Biologist Examines Life From Molecules To Humanity

Self and the Beginning of Life 27

“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity

Fig. 3.6. Formation of protein and its conformation. (A) Two individual amino acids
joined by a peptide linkage (amide bond) to form a dipeptide. “R” refers to the side
chain of an amino acid. The twenty different amino acids in a protein differ from one
another by the side chains they carry. Therefore, there are twenty different kinds of side
chains in a protein molecule, the combined effect of which imparts the uniqueness of
a protein. (B) Drawing showing how a protein (a long chain of amino acids) is folded to
form 3-dimensional secondary, tertiary, and quaternary structures. [US Natl. Lib. Med.]