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Unformatted text preview: Biology notes: 10-10-08 I. Protein Denaturation: a. I r reversible change in the three0dimensional structure of a protein i. Weak bonds: H-, ionic, hydrophobic, Van der Waals b. Once broken may recreate them inappropriately c. The energy of folding a protein is low (-5 to -15 Cal/mol), so proteins are easy to denature, but is it also easy just to change their shape in minor ways. How could this be useful? Pick an analogy that applies i. It I easy to turn a cell phone off by closing the lid ii. I crumple up a newspaper before throwing it away iii. I can pass my computers electronic cord through a hole by uncoiling it iv. A slinky walks down a stair by coiling and uncoiling d. Example of protein denaturation: egg whites i. Do not mix egg whites directly with gin 1. Alcohol is hydrophobic 2. Unwinds egg whites 3. Egg whites reform with inappropriate bonds 4. Gooey mess e. Denaturation is why heat, acid, alcohol destroy living cells Membrane Structure and Function I. Membrane structure a. Lipid bilayer hydrophobic fatty acid interior b. Phosphate+ group exterior c. Proteins incorporated into the bilater i. Hydrophobic amino acid side chains ii. Hydrophilic amino acid side cains iii. Transmembrane alpha-helix iv. Extracellular carbohydrates v. fluid mosaic model vi. Often islands of protein complexes vii.Proteins can move back and forth in the membrane d. In a channel, the edges, away from the center of the hole, they tend to be hydrophobic(interact with the fatty acid tails) toward the center, the...
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This note was uploaded on 10/14/2009 for the course BIS 64982 taught by Professor Comai during the Spring '09 term at UC Davis.
- Spring '09