14. Under normal circumstances: A. Adult hemoglobin (Hb) binds to oxygen more tightly than myoglobin (Mb) binds. B. Fetal Hb binds oxygen more tightly than adult Hb. C. Adult Hb binds oxygen more tightly than either fetal Hb or Mb binds. D. Mb has the lowest affinity for oxygen of the 3 proteins. 15. Which of the following information belong to the tertiary structure of the protein? A. The prosthetic group interacting with the polypeptide through dipole-dipole interactions B. The side chain of the serine residue at the 57th position interacts with the side chain of the histidine at the 109th position through dipole-dipole interactions C. Both A and B D. Neither A nor B

1. What is the isoelectric point (pI) of lysine which has pKa values of 2.1 for the α carboxyl group, 9.7 for the α amino group and 10.5 for the side chain amino group? 2. Which of the following is most likely to be found on the exterior of a protein? A) Pro B) Trp C) Ser D) Glu 3. The type of reaction that forms a peptide bond is A) Elimination B) Hydrolysis C) Nucleophilic substitution D) Condensation

1. Most globular proteins are denatured and lose their activity when briefly heated to 65°C. However, globular proteins that contain multiple disulfide bonds often must be heated longer and at higher temperatures to denature them. Furthermore, upon cooling of the denatured proteins, the activity of these proteins can often be restored. Explain these properties.

2. Consider the following quaternary cartoon structure below, where each colored shape represents a different subunit. i. ii. iii. How many N-termini are there in this complex? Suppose the blue square and orange triangle subunit are held together by a disulfide bond, sketch below what you would expect to see after the addition of BME. What kind of interactions may be responsible for holding the orange triangle and green circle subunits together? List at least three.