Proteins

A macromolecule is made of amino acid monomers
Amino Acids are made of a central carbon bonded to a carboxyl group, an amino group, and an “R” group (can be different atoms/molecules), and an H atom
Of the 20 amino acids, all of them have the same basic structure. They are defined by the R group they possess.
Nonpolar -R groups are hydrophobic
Polar -R groups are hydrophilic
Proteins contain many amino acids and are often amphiphilic(both hydrophobic & philic)

A polymer of 2 or more amino acids
Named for the number of amino acids they contain
dipeptides have 2, tripeptides have 3
oligopeptides have fewer than 10 to 15
polypeptides have more than 15
proteins have more than 100•Dehydration synthesis creates a peptide bond that joins amino acids

Primary Structure: a linear sequence of amino acids
Secondary Structure: when the amino acids (aa) in a primary structure interact with each other (e.g. hydrogen bonding, vanderwaals interactions, etc.), the linear chain may begin to coil into an alpha helix or fold into a fan shape (beta pleated sheet)
Tertiary Structure: when continued amino acid interactions cause the peptide to take on a 3D structure
Quaternary Structure: when multiple polypeptides interact

Conformation - overall 3-D shape is crucial to function
important property of proteins is the ability to change their conformation
Example: opening and closing of cell membrane pores
Denaturation: drastic conformational change that destroys the function of a protein, occurs with extreme heat or pH, often permanent