B M B 401 Lecture Notes - Lecture 5: Central Cross-Island Highway, Inflection Point, Duodenum

• School: PSU
• Department: Biochemistry and Molecular Biology
• Course: B M B 401
• Professor: Howell Paul

Document Summary

Bmb 401 lecture 5 ph and pka. Weak acids only disassociate partially in water. In order to counter balance an overall rise in [h+], [oh-] must decrease. Some h+ will react with oh- until the numbers balance out so that [h+][oh-] = 10-14. Reaction a h2o h+ + oh- Reaction b ha(weak acid) h+ + a- While adding oh- pushes reaction a to the left, the h+ gets consumed by the oh- and reaction b gets pushed to the right. Point of inflection point where [ha] = [a-]; the point where ph = pka. Henderson-hasslebach equation : ph = pka + log () + nh3 + h: at low phs it is protonated, and therefore charged, at high phs, it is dissociated and therefore neutral. Weak acids: ha a- +h, at low phs it is protonated and therefore neutral, at high phs it is disassociated and therefore charged. Ionization state affects drug absorption by passive diffusion across a membrane.