Chapter Twentyfive Synthetic and Natural Organic Polymers Chapter

Chapter Twenty-five Synthetic and Natural Organic Polymers

Chapter Twenty-Five/ Synthetic and Natural Organic Polymers Proteins • Polymers: are large molecules made up of repeating units called Monomers. • Proteins are polymers of amino acids; they play a key role in nearly all biological processes. • Enzymes, the catalysts of biochemical reactions, are mostly proteins. Proteins also facilitate a wide range of other functions, such as transport and storage of vital substances, coordinated motion, mechanical support, and protection against diseases. The human body contains an estimated 100, 000 different kinds of proteins, each of which has a specific physiological function. • Proteins have large molar masses, ranging from about 5000 g to 1 x 107 g • The basic structural units of proteins are amino acids. • amino acid is a compound that contains at least one amino group (-NH 2) and at least one carboxyl group (-COOH):

Chapter Twenty-Five/ Synthetic and Natural Organic Polymers Proteins Amino acids in solution at neutral p. H exist as dipolar ions, meaning that the proton on the carboxyl group has migrated to the amino group.

Chapter Twenty-Five/ Synthetic and Natural Organic Polymers Proteins The first step in the synthesis of a protein molecule is a condensation reaction between an amino group on one amino acid and a carboxyl group on another amino acid. The molecule formed from the two amino acids is called a dipeptide, and the bond joining them together is a peptide bond: +H 3 N H O C C O- + +H 3 N H O C C O- R 2 R 1 +H 3 N Peptide bond H O C C R 1 H O N C C O - + H 2 O H R 2 -CO-NH- is called the amide group.

Chapter Twenty-Five/ Synthetic and Natural Organic Polymers Proteins Example A protein is: A) a polymer of amino acids C) an addition polymer B) a fatty acid ester of glycerol D) a polymer of fatty acids Example The formula CH 3 CH 2 CH 2 CH 2 OH represents: a-an alcohol b-an alkene c-an alkyne d-an unsaturated hydrocarbon Example Which of the following is a ketone? a-CH 3 CH 2 COCH 3 b-CH 3 CH 2 CHO c-CH 3 OCH 3 d-CH 3 CH 2 COOH

Chapter Twenty-Five/ Synthetic and Natural Organic Polymers Proteins Example Classify each of the following molecules as: alcohol, aldehyde, ketone, carboxylic acid, ether, amine or amino acid ether amine aldehyde ketone Carboxylic acid alcohol Amino acid