AP Bio U3

Enzymes

Biological catalysts (proteins) that speed up biochemical proteins —> lowers activation energy requirements

contain an active site to interact w substrates - must be compatible

can have chemical charge(s)

substrate

molecule that can interact w an enzyme

enzyme concentration

cells typically maintain a specific concentration

can facilitate synthesis/digestion reactions

proteins

made up of linear chains of amino acids

Amino acids

connected by formation of covalent bonds at carboxyl terrminus of growing peptide chain

Primary structure

determined by sequence of amino acids held together by covalent (peptide) bonds

secondary structure

arises through local folding of amino acid chain into elements

• alpha helices + beta sheets

Tertiary structure

overall 3D shape of protein and often minimizes free energy; various types of bonds + interactions stabilize the protein during this structure

Quaternary structure

arises from interactions between multiple polypeptide units