BIOC 2580 Lecture Notes - Lecture 2: Deprotonation, Electronegativity, Acid Dissociation Constant

• School: University of Guelph
• Department: Biochemistry
• Course: BIOC 2580
• Professor: Enoka Wijekoon

Document Summary

Biochemical! reactions! occur! in! aqueous! solution! at! close! to! neutral! ph. Many! biochemical! substances! such! as! amino! acids! include! weak! acid! groups! such! as! carboxylates,!sh!or!phenolic!oh,!or!weak!bases!such!as!amines!or!some!ring!n!compounds. These! side! chains! are! dominated! by! hydrocarbon,! i. e. consists!only!of!c;c!and!c;h!bonds,!e. g. hydrocarbon,! i. e. consists!only!of!c;c!and!c;h!bonds,!e. g. !valine* Hydrocarbon! is* non;polar* and* hydrophobic,! or! water! avoiding. Polarity! in! a! molecule! have! very! different! electronegativity. ! Electronegativity! refers! to! the! tendency! of! a! nucleus! to! hold! electrons! (it! does!not*mean!possession!of!negative!charge). is! a! property! that! occurs! when! atoms! attract. H! have! similar! electronegativity,! bonding! electrons! are* evenly* distributed* in! hydrocarbon!regions. Curly arrow means electrons moved similar electronegativity more electronegative atoms get 50%+ share. Nonipolar! groups! interact! well! with! each! other! and! poorly! with! polar! groups. ! H2o,! a! property! known! as! the! hydrophobic* effect. ! Although! it"s! a! nonipolar! bond,! it"s! not! large! enough! to! make! the! whole! molecule! very! noni polar. Nh2 > instead of nh3 like the others so it"s not as polar.