Proteins Multipurpose molecules Regents Biology 2006 2007 Proteins

Proteins: Multipurpose molecules Regents Biology 2006 -2007

Proteins Examples u muscle u skin, hair, fingernails, claws § collagen, keratin u insulin pepsin § digestive enzyme in stomach u insulin § hormone that controls blood sugar levels collagen (skin) Regents Biology

Proteins § Function: u many, many functions § hormones w signals from one body system to another w insulin § movement w muscle § immune system w protect against germs § enzymes Regents Biology w help chemical reactions

Proteins § Building block = amino acids amino amino acid – acid u 20 different amino acids H O H | || —N— —C—C—OH | H variable Regents Biology group There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

Amino acid chains § Proteins u amino acids chained into a polymer amino acid amino acid § Each amino acid is different u some “like” water & dissolve in it u some “fear” water & separate from it Regents Biology

Water-fearing amino acids § Hydrophobic “water fearing” amino acids u try to get away from water in cell u § the protein folds Regents Biology

Water-loving amino acids § Hydrophillic “water loving” amino acids u try to stay in water in cell u § the protein folds Regents Biology

For proteins: SHAPE matters! § Proteins fold & twist into 3 -D shape u that’s what happens in the cell! § Different shapes = different jobs growth hormone Regents Biology hemoglobin pepsin collagen

It’s SHAPE that matters! § Proteins do their jobs, because § of their shape Unfolding a protein destroys its shape wrong shape = can’t do its job u unfolding proteins = “denature” u § temperature § p. H (acidity) Regents Biology folded unfolded “denatured”