Biochemistry Exam 2 (Multiple Choice) Guide 2024

What is the organic portion of the heme group in hemoglobin? - Correct Answer Protoporphyrin Define superoxide. - Correct Answer 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 Answer 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 Answer Histidine Define myoglobin. - Correct Answer Molecule whose function is to store oxygen in muscle cells What type of binding is indicated by a sigmoidal-shaped binding curve? - Correct Answer Cooperative Under normal conditions, the heme iron in myoglobin and hemoglobin is in what oxidation state? - Correct Answer Fe2+ How can the structure of normal adult hemoglobin be described? - Correct Answer A tetramer composed of two alpha-beta dimers True or false: Hemoglobin exhibits cooperative binding of O2 while myoglobin does not. - Correct Answer True True or false: Both myoglobin and hemoglobin are tetrametric proteins. - Correct Answer False True or false: Hemoglobin exhibits a hyperbolic O2 saturation curve while myoglobin exhibits a sigmoid shaped curve. - Correct Answer False True or false: Hemoglobin exhibits a higher degree of O2 saturation at all physiologically relevant partial pressures of O2 than does myoglobin. - Correct Answer False Hemoglobin's binding of oxygen is best described as what? - Correct Answer Combination of sequential and concerted models What factor influences the binding of oxygen to myoglobin? - Correct Answer The partial pressure of oxygen, pO2