PROTEINS
Characteristics of Proteins
• Contain carbon, hydrogen, oxygen, and
nitrogen
• Serve as structural components of
animals in growth, maintenance and
repair
• Also can serve as control molecules
(enzymes) inside organisms
• Also can as transport and messenger
molecules
• The basic building block of proteins are
the amino acids (total of 20 of these)
Amino Acid
• Amino group gives AA its amino properties.
• Carboxyl group acts like an acid, and give it its acid
properties
• “R” group varies between each of the 20 AA’s. This is
what makes each of the AA’s different and unique.
• Two amino acids join together to form a dipeptide, the
spot where they join is called a peptide bond
•Most proteins are know as polypeptides, because they
are long chains of AA’s.
Amino Acids Structures-AA’s
usually end in “ine”
Some More Amino Acids
Still More Amino Acids
Formation of a Dipeptide
Dehydration synthesis
Amino Acid + Amino Acid = Dipeptide
3 amino acids linked = Tripeptide
100’s of AA’s linked = Polypeptide
A protein consists of one or more
polypeptide chains.
Enzymes a very important
protein molecule
• These are polypeptides that
regulate the chemical reactions in
all living things.
• Enzymes control the rate of
reactions and lower the activation
energy to get reactions started
without being used up or altered in
the reaction.