1University of HoustonBCHS 3304: General Biochemistry I - Fall 2008Section 12697 Tuesday/Thursday 11:30 AM – 1:00 PM 102 SWExam 1 OverviewCondensation reactions•Chemical Evolution, simple molecules condense to form more complex forms (polymers)Reaction of a carboxylic acid with an amineReplication through complementarity• Specific pairing of functional groups gives rise to complementarity• More complex molecules increases chemical versatilityy• Complementarity makes it possible for macromolecules to replicate• Over time natural selection favored molecules that made accurate copies of themselvesGibb’s Free Energy• Is a state function (a property of a system that depends only on the current state of the system and not its history)• Gibb’s Free Energy is determined at constant T and P: G=H-TS•The Gibbs free energy (G) of a system is defined by an enthalpy term (H) (change of the total energy with the system), and the entropy term (S) (change in the disorder) at temperature (T)G H -TSΔG°= ΔH°-TΔS°The van’t Hoff Relationship• Methodology of finding ΔH and ΔS from experimental data.lnKeq=−ΔG°RT=−ΔH°−TΔS°RT⎛ ⎝ ⎜ ⎞ ⎠ ⎟ 1ΔH°⎛ ⎞ Va n’t Hoff plotlnKeq=1RΔS°−ΔH°T⎛ ⎝ ⎜ ⎞ ⎠ ⎟ RST1RH- lnKooeqΔ+⎟⎠⎞⎜⎝⎛Δ=lnKeqRH-oΔ= SlopeRSoΔT1= InterceptVa n t Hoff plot2Structure & Properties of WaterBent geometry, O-H bond length of 0.958Å Can form Hydrogen bondsNonpolar/Polar Interactions and Structured WaterA cage of water molecules (calatherate) surrounding the non-polar molecule. This cage has more structure than the surrounding bulk media.ΔG = ΔH -TΔSTo minimize the structure of water the hydrophobic molecules cluster together minimizing the surface area. Henderson - Hasselbalch equation][]][[HAAHK−+=From][][][−+=AHAKHRearrange][ATake (-)Log of each][][loglogHAAKpH−+−=][][logHAApKpH−+=Titration curve for phosphateKey to structureGAVL(1)IMPFWSTN(2)QYC3KR(3)HDEThe Fischer ConventionAbsolute configuration about an asymmetric carbonrelated to glyceraldehyde (+) = D-Glyceraldehyde(-) = L-Glyceraldehyde123456789101112131415H3N+-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-COO-A-TF - M - A - TA- K - F - MQ-M-A-KD-I-K-Q-MG-M-D-I-KY-R-G-MY-R-G-MY-RCyanogen Bromide (CNBr) Cleaves after Met i.e M - XD -I -K -Q -M A - TA -K -F -MY -R -G -MTrypsin cleaves after K or R (positively charged amino acids)Q - M - A - KG -M -D -I -KF - M - A - TY -