PROTEINS
DEFINITION and
ETYMOLOGY
COMPOSITION
R GROUP
CLASSIFICATION
• a class of biomolecules which makes
up more than 50% of the cell's dry
weight
• comes from Greek "proteios" -> first
place
• hundreds to thousands of amino
acids linked by peptide bonds,
• each amino acid is one of 20
possible and is made of a carbon,
amino group, carboxyl group,
hydrogen atom and R group
• each of 20 R groups correspond to
one type of amino acid
• determines an amino acid's
characteristics
• can be classified based on:
• type (antibody, compliment,
enzyme, hormone, etc.)
• function (enzymatic, structural,
transport, hormonal, receptor,
contractile and defensive)
• structure and composition