AAB MT Hematology 2023 Practice Test Questions With Complete Solution

AAB MT Hematology 2023 Practice Test Questions With Complete Solution What is hemoglobin composed of? - CORRECT ANSWERS 4 heme, 4 iron, 4 globins What disorder does a defect in heme synthesis lead to? - CORRECT ANSWERS Porphyria Porphyria - CORRECT ANSWERS Deficiency in the enzymes of the porphyrin pathway leads to insufficient production of heme. The principal problem in these deficiencies is the accumulation of porphyrins, the heme precursors, which are toxic to tissue in high concentrations. What is methemoglobin? - CORRECT ANSWERS Methemoglobin is a form of hemoglobin that contains ferric [Fe3+] iron and has a decreased ability to bind oxygen. However, the ferric iron has an increased affinity for bound oxygen. When methemoglobin concentration is elevated in red blood cells, tissue hypoxia can occur. What is the function of the enzyme methemoglobin-cytochrome C reductase in a red blood cell? - CORRECT ANSWERS To keep iron in the ferrous state What product is formed when ferrous iron of hemoglobin is oxidized to the ferric state? - CORRECT ANSWERS Methemoglobin What is carboxyhemoglobin? - CORRECT ANSWERS A stable complex of carbon monoxide and hemoglobin that forms in RBCs when carbon monoxide is inhaled or produced in normal metabolism. Large quantities of it hinder delivery of O2 to the body. Tobacco smoking (through carbon monoxide inhalation) raises the blood levels of COHb by a factor of several times from its normal concentrations. Which hemoglobin has a 200 times greater binding capacity for the hemoglobin molecule than oxygen? - CORRECT ANSWERS Carboxyhemoglobin Which hemoglobin derivative causes irreversible changes in RBCs? - CORRECT ANSWERS Sulfhemoglobin -- makes blood incapable of carrying oxygen. Which of the following hemoglobins is NOT normally present in a normal adult? - CORRECT ANSWERS Hb-S Which embryonic hemoglobin is normally found in newborns? - CORRECT ANSWERS Hb-F What is the most abundant hemoglobin in a newborn? - CORRECT ANSWERS Hb-F What is the molecular structure of Hemoglobin S? - CORRECT ANSWERS Valine replaces glutamic acid in the 6th position of the beta chain Which of the following hemoglobins is insoluble under lowered oxygen tension? - CORRECT ANSWERS Hb-S What laboratory test is used to confirm the specific diagnosis of sickle cell anemia? - CORRECT ANSWERS Hemoglobin electrophoresis In the solubility test for hemoglobin S, what is the reagent responsible for the reduction of the hemoglobin molecule? - CORRECT ANSWERS Sodium dithionite In hemoglobin C, what replaces glutamic acid? - CORRECT ANSWERS Lysine Which red blood cell inclusion is characteristic of hemoglobin C disease? - CORRECT ANSWERS Rod-shaped crystals What is hemoglobin F composed of? - CORRECT ANSWERS 2 alpha and 2 gamma chains Which hemoglobin is resistant to alkali denaturation? - CORRECT ANSWERS Hb-F Which hemoglobins are differentiated by the Kleihauer-Betke technique? - CORRECT ANSWERS Hb-A1 from Hb-F What is the order of migration of hemoglobins, from fastest to slowest, on cellulose acetate at pH 8.4? - CORRECT ANSWERS A1, F, S, C