BIO 201 Lecture 3: Proteins
7 Feb 2017
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Document Summary
Molecules with the same chemical formula but different arrangements of atoms are. Non-superimposable (non-identical), mirror image isomers can rotate polarized light. Either left- (levo; l) or right-handed (dextro; d) Mirror images of each other but not superimposable (not identical) When carbon is bound to any 4 different atoms/groups, molecule is chiral. If any 2 are the same, mirror images are superimposable (the same thing) Glycine is the exception (has 2 h) Amino acids are defined by their side chains (r-groups) Hydrophobic (don"t like being in cell water hating) Contains -oh or both -nh2 and c=o. Contain -nh2 (basic + at ph 7) (may look like nh3+) Or -cooh (acidic - at ph 7) (may look like (coo-) Can form covalent (cid:1445)disulfide(cid:1446) bonds (--s--s--) usually extracellular in oxidizing environments. R-group covalently bonded to backbone n in side chain. Restricts flexibility of backbone (cid:1445)helix breaker(cid:1446) Oxidation is loss, reduction is gain (oil rig) of electrons.
