3S: Proteins Shireen Rudina
What do proteins do? • Structure • Collagen in skin, keratin in hair and nails • Signaling between cells • Defend against disease • Antibodies • Facilitate Reactions (enzymes) • Do essential work in each cell
Which of these are proteins: • DNA • Fibers in your heart muscle • ? • ?
Catalase is an enzyme 2H2O2 2H2O + O2 + heat Does not happen spontaneously, only in the presence of catalase.
Polypeptide • Many amino acids connected by peptide bonds polypeptides
Primary Structure • Order of amino acids linked together in a long chain • One end carboxyl & one end amino
Secondary Structure • Chain of a.a.sbends based on the R groups Alpha helix or Beta pleated sheets
Tertiary Structure • Further folding of the polypeptide chain • Disulfide bridges
Quaternary Structure • Different polypeptide chains come together to form the final protein