Student No .: Course: BCHM Page 1 of 10 QUEEN'S UNIVERSITY EXAMINATIONS - 9 OCTOBER 2019 Faculty of Arts & Science Biochemistry 310 and 315 Dr. Robert Campbell and Dr. Steven Smith INSTRUCTIONS 1. Enter your student number and course section in the appropriate places on this Exam Paper. 2. There are 9 Short-Answer questions. Please complete the Short-Answer questions in the space provided in the exam. 3. HAND IN THIS EXAM PAPER 4. The exam duration is 90 minutes. Q1 Q2 Q3 Q4 Q5 Total /43 /6 /12 /12 /7 /6
Student No .: Course: BCHM The following table of pK values may be useful: Amino acid Alanine 2.3 Arginine 2.2 Asparagine 2.0 Aspartate 1.9 Cysteine 2.0 Glutamine 2.2 Glutamate 2.2 Glycine 2.3 Histidine 1.8 Isoleucine 2.4 Leucine 2.4 Lysine 2.2 Methionine 2.3 Phenylalanine 1.8 Proline 2.0 Serine Threonine Tryptophan Tyrosine Valine pK? (-COOH) 2.2 2.1 2.4 2.2 2.3 Page 2 of 10 pK2 (-NH3+) 9.7 9.0 8.8 9.6 10.3 9.1 9.7 9.6 9.2 9.7 9.6 9.0 9.2 9.1 11.0 9.1 9.6 9.4 9.1 9.6 pKR (R group) 12.5 3.6 8.2 4.2 6.0 10.5 10.0
Student No .: Course: BCHM Page 3 of 10 1. (total 6 marks) When a protein folds, there is a tendency for the hydrophobic side chains to aggregate and be buried inside the protein. This is governed by the free energy change (AG). For each of the interactions or groups below, describe their contributions to AH or AS (small or large, positive or negative, or zero) and how that ultimately affects AG of the folding process. a) The interaction of the hydrophobic side chains with each other (2 marks). b) The interaction of water with the hydrophobic side chains in the unfolded state (2 marks). c) The interaction of water molecules with the polar groups of the protein in the unfolded state. (2 marks).