Multipurpose molecules Proteins: Multipurpose molecules 2006-2007

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

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

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

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

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

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

For proteins: SHAPE matters! Proteins fold & twist into 3-D shape that’s what happens in the cell! Different shapes = different jobs growth hormone 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 unfolding proteins = “denature” temperature pH (acidity) unfolded “denatured” folded