GENERAL BIOCHEMISTRY Drawback Set No. 1 Answered by: Andrea Rose A. Fajardo of BSFT 2-1N 1. Calculate the pH of a dilute resolution that comprises a molar ratio of potassium acetate to acetic acid (pKa=Four. 76) of: a. 2:1 pH = Four. 76 + log[2]/[1] = Four. 76 + Zero. 3010 = 5. 06 b. 1:Four pH = Four. 76 + log[1]/[4] = Four. 76 + (-Zero. 6021) = Four. 16 c. 6:5 pH = Four. 76 + log[6]/[5] = Four. 76 + Zero. 0792 = Four. 81 d. 2:three pH = Four. 76 + log[2]/[3] = Four. 76 + (-Zero. 1761) = Four. 58 e. 9:1 pH = Four. 76 + log[9]/[1] = Four. 76 + Zero. 9542 = 5. 71 2. A buffer comprises Zero. 01mol of lactic acid (pKa=three. 86) and Zero. 05mol of sodium lactate per liter. a. What’s the ensuing pH of the buffer? H = three. 86 + log[0. 05]/[0. 01] = three. 86 + Zero. 6990 = Four. 56 b. Calculate the change in pH when 5mL of Zero. 5M HCl is added to 1L of buffer. 5mL of Zero. 5 mol/L 5mL * 1L/1000mL = Zero. Zero05L Zero. Zero05L * Zero. 5 mol/L = Zero. 0025mol NaC3H5O3 = Zero. 05mol – Zero. 0025mol = Zero. 0475 C3H5O3 = Zero. 01mol – Zero. 0025mol =Zero. 0075 pH = three. 86 + log[0. 0475]/[0. 0075] = three. 86 + Zero. 8016 = Four. 66 • Four. 55-Four. 66 = Zero. 11 is the change in pH c. What pH change would you count on for those who added the same amount of HCl to 1L of pure water? [H+] = (Zero. 0025mol)(1L) = Zero. 0025M pH = -log Zero. 0025 = 2. 60 three. The construction of the amino acid of isoleucine is given on the proper. a.
What number of chiral facilities does it have? 2 b. What number of optic isomers? Four c. Draw the angle formulation for all of the optical isomers of isoleucine. [pic] Four. A peptide has the sequence: Glu-His-Trp-Ser-Leu-Arg-Professional-Gly a. What’s the cost of the molecules at pH Four and 11? (Use pKa values of these within the ppt) |pH |NH3+ |Glu |His |Arg |COO- |Internet Cost | |Four |+1 |-1 |Zero |+1 |-1 |Zero | |11 |Zero |-1 |Zero |+1 |-1 |-1 | . What’s the pI for the peptide? | |pKaCOOH |pKaNH3 |pKaR | |Glu |2. 19 |9. 67 |Four. 25 | |His |1. 82 |9. 17 |6. 04 | |Trp |2. 83 |9. 39 | | |Ser |2. 1 |9. 15 | | |Gly |2. 34 |9. 60 | | |Leu |2. 63 |9. 60 | | |Arg |2. 17 |9. 04 |12. 48 | |Professional |1. 99 |10. 60 | | |Gly |2. Four |9. 60 | | 2. 34 6. 04 9. 67 12. 48 pI = 6. 04 + 9. 67 / 2 = 7. 85 5. Histidine has three ionisable practical teams. Write the equilibrium equations for its three ionizations and assign the right pKa for every ionization. Draw the construction of histidine in every ionization state. What’s the web cost of the histidine molecules in every ionization state? STRUCTURE OF IONIZATION IN EACH IONIZATION STATE [pic] NET CHARGE Construction |Internet Cost | |+H3N–CH–(RH+)–COOH |+2 | |+H3N–CH–(RH+)–COO- |+1 | |+H3N–CH–(R)–COO- |Zero | |H2N–CH–(R)–COO- |-1 | ———————– -2 +1 +2 -1 Zero
