Question

9. What does a reducing agent such as beta-mercaptoethanol OH-CH2-CH2 -SH do in the process of straightening curly hair? 10. Think about the changes of ionization state of amino acids in general and more specific the amino acid Histidine at different pH. The charge in this residue depends on the environment. How can a protein act as a buffer in the cell?

Answer 1

DATE: PAGE exotein Keratin 9 Hair is made up of keratin protein keral has long chain of amino acids containe kadrough Sulbhuana emine-acids o acids. To Sulphur atom presents o in amina ar of keto keration forms me disulfide bond amino acid. with other containing sulfuscootalking T disulphide bond Because of this the hair turned into In order to get st straight hair this disulfide bond needs to be broken. B-mercapto ethanol reduces disulfide bond such as - a pomercapto ethan misms العيد ss Smsm So, that the strands remain single and a Ionisation state of an amino acid varies with pH. In acidic solution the amino group is protonat (-34) and carboxyl Ugonbi's net dissociated ( -coon). U As the pH is increased the carboxylic and group first give up the Ht and form ooo and the the in group gets converted into ha il neutral state

DATE: PAGE - Lonisation state of Histidines - P WHg Histidine. te-on A NH3 1-2: total total corget charge = +2 +2 Z: +: total charge = 1 - Iwitter ion. Total charge = 0 Fly I exists at LB exists at pH <1.82 (highly acidic NH pH range 1,8< pH 6.02. pH range 602 cpH <9.17 roop pH>9.17. 'C' exists at D exist at

DATEJ- CS PAGE A_Kc Different pH provide different charge present on the amino acid This shows the charge in the moleale depende on the environment Protein contains amino acids and each anino acid has different ionization state at different pH some fructures exist at a pH ramme for example histidine 'B' state exist . at 1.824046.02. And as we know a buffer is that solution which resists the change in phatnarrow range, and a