3.38 Protein Classification
Protein Structure
Amino acids are the “building blocks” of proteins. There are 20 different amino acids. The structural formula of the
simplest amino acid, called glycine, is shown in theFigure3.72. Other amino acids have slightly different structures.
A protein molecule is made from one or more long chains of amino acids, each linked to its neighbors by covalent
bonds. If a protein has more than one chain, the chains are held together by weaker bonds, such as hydrogen bonds.
FIGURE 3.72
The sequence of amino acids in chains and the number of chains in a protein determine the protein’s shape. The
shape of a protein, in turn, determines its function. Shapes may be very complex. You can learn more about the
shapes of proteins at the URL below.
http://www.youtube.com/watch?v=lijQ3a8yUYQ
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/5092Q:What do you think the “ribbons” in the colorful hemoglobin molecule pictured in the opening image represent?
A:The “ribbons” represent chains of amino acids.