BIOCHEM C785 POSSIBLE FINAL EXAM 2021

Myoglobin and hemoglobin each have different numbers of subunits and this affects their respective oxygen storage and delivery capabilities. How many subunits do myoglobin and hemoglobin each have? Select one: a. Two, Three b. One, Two c. One, Four Correct! Myoglobin consist of one and hemoglobin consists of four subunits. The number of subunits affects their respective oxygen storage and delivery capabilities. d. Four, One Addition of ______________________alters the shape of the iron–heme complex, and therefore its absorption of light as indicated by its color change from dark purple (the color of hemoglobin in venous blood) to brilliant scarlet (the color of hemoglobin in arterial blood). Select one: a. iron b. oxygen Correct! c. globin subunit d. porphyrin Oxygen binding alters the structure of an entire hemoglobin tetramer, so the structures of oxyhemoglobin and deoxyhemoglobin are noticeably different. The oxyhemoglobin conformation is specifically referred to as the __________ state, whereas the deoxyhemoglobin conformation is referred to as the __________ state. Select one: a. O and D b. Oxygenated and Deoxygenated c. Relaxed or R and Tense or T Correct! Oxygen binding causes a marked change in hemoglobin structure. In the presence of oxygen, hemoglobin is in the Relaxed state or R state. In the absence of oxygen, hemoglobin is in the Tense state or T state. d. There is no difference between the two states Patients with sickle cell anemia have atypical hemoglobin, which will distort the red blood cells into sickle shape during oxygen delivery. The substitution of a hydrophilic amino acid with a ____________amino acid in hemoglobin subunits results in the polymerization of hemoglobin, leading to the sickling of red blood cells. Select one: a. hydrophobic Correct! In case of sickle cell anemia, a hydrophilic amino acid-glutamate is replaced by a non polar-hydrophobic amino acid-valine, leading to polymerization of hemoglobin, fibril formation and eventually sickling of the red blood cells. b. cysteine c. polar This study source was downloaded by from CourseH on 11-10-2021 05:51:04 GMT -06:00