Biochemistry Exam 2 (Multiple Choice) Questions with Complete Solutions (Latest 2025) What is the organic portion of the heme group in hemoglobin? - Correct Answers ✅Protoporphyrin Define superoxide. - Correct Answers ✅A reactive oxygen species that is damaging to biological materials What is the chemical form in which most of the carbon dioxide is transported in the blood? - Correct Answers ✅Bicarbonate ion In hemoglobin, the iron of the heme is bonded to the four nitrogens of porphyrin and to the proximal _____ residue of the globin chain. - Correct Answers ✅Histidine Define myoglobin. - Correct Answers ✅Molecule whose function is to store oxygen in muscle cells What type of binding is indicated by a sigmoidal-shaped binding curve? - Correct Answers ✅Cooperative Under normal conditions, the heme iron in myoglobin and hemoglobin is in what oxidation state? - Correct Answers ✅Fe2+ 1 / 3
Biochemistry Exam 2 (Multiple Choice) Questions with Complete Solutions (Latest 2025) How can the structure of normal adult hemoglobin be described? - Correct Answers ✅A tetramer composed of two alpha-beta dimers
True or false: Hemoglobin exhibits cooperative binding of O2
while myoglobin does not. - Correct Answers ✅True
True or false: Both myoglobin and hemoglobin are tetrametric
proteins. - Correct Answers ✅False
True or false: Hemoglobin exhibits a hyperbolic O2 saturation
curve while myoglobin exhibits a sigmoid shaped curve. - Correct Answers ✅False
True or false: Hemoglobin exhibits a higher degree of O2
saturation at all physiologically relevant partial pressures of O2 than does myoglobin. - Correct Answers ✅False Hemoglobin's binding of oxygen is best described as what? - Correct Answers ✅Combination of sequential and concerted models What factor influences the binding of oxygen to myoglobin? - Correct Answers ✅The partial pressure of oxygen, pO2 2 / 3
Biochemistry Exam 2 (Multiple Choice) Questions with Complete Solutions (Latest 2025)
True or false: Concerning myoglobin, the globin chain
contains an extensive alpha-helix structure. - Correct Answers ✅True
True or false: Concerning myoglobin, the heme group is
bound to the globin chain by two disulfide bonds to cysteine residues. - Correct Answers ✅False
True or false: Concerning myoglobin, the iron of the heme
group is in the Fe3+ oxidation state. - Correct Answers ✅False - Fe2+
True or false: Concerning myoglobin, the diameter of the iron
ion decreases upon binding to oxygen. - Correct Answers ✅True What is true regarding hemoglobin and oxygen transport? - Correct Answers ✅Hemoglobin binds more oxygen as the pH is lowered What is sickle-cell anemia caused by? - Correct Answers ✅Substitution of a Val residue for a Glu residue at the beta-6 position
- / 3