front 1 A bleeding patient has impaired platelet attachment to exposed subendothelium despite a normal platelet count. Which protein is most directly deficient? A. von Willebrand factor | back 1 A. von Willebrand factor |
front 2 A deep vascular laceration exposes tissue factor to circulating blood. Which pair is ultimately generated downstream? A. Plasmin and protein C | back 2 D. Thrombin and factor XIII |
front 3 Which pair of coagulation proteins primarily serves as binding proteins? A. II and X | back 3 B. V and VIII |
front 4 A patient with severe chronic liver failure has reduced synthesis of the most important serum protein. Which protein is it? A. Haptoglobin | back 4 C. Albumin |
front 5 A monoclonal spike on serum electrophoresis reflects proliferation of which immunoglobulin-secreting cell? A. Plasma cell | back 5 A. Plasma cell |
front 6 Failure of which plasma system most directly impairs clearance of circulating antigen-antibody complexes? A. Kallikrein system | back 6 B. Complement system |
front 7 Which combination can activate complement in the way described here? A. Heparin and platelet factor 4 | back 7 D. Immune complexes and bacterial polysaccharides |
front 8 The major serine protease inhibitor of human plasma is: A. C1 esterase inhibitor | back 8 C. α1-antitrypsin |
front 9 Which amino acid residue is necessary for α1-antitrypsin binding to proteases? A. Methionine 358 | back 9 A. Methionine 358 |
front 10 Markedly decreased hepatic secretion of α1-antitrypsin is most likely due to: A. Promoter methylation | back 10 D. Point mutation in exon 5 |
front 11 A patient develops antibodies against platelet glycoproteins with no discernible cause. Which diagnosis best fits? A. Hemolytic uremic syndrome | back 11 B. Idiopathic thrombocytopenic purpura |
front 12 Which substance is characteristically stored in platelet electron-dense granules? A. Platelet-derived growth factor | back 12 C. Serotonin |
front 13 Which molecule is a classic constituent of platelet α-granules? A. Fibrinogen | back 13 A. Fibrinogen |
front 14 Platelet lysosomal granules characteristically contain: A. ADP and ATP | back 14 D. Hydrolytic enzymes |
front 15 Which set lists the three fundamental platelet mechanisms in coagulation? A. Activation, inhibition, lysis | back 15 B. Adhesion, aggregation, secretion |
front 16 A patient lacking von Willebrand factor would rapidly clear which coagulation factor from plasma? A. Factor V | back 16 C. Factor VIII |
front 17 Binding of collagen to platelet glycoprotein GPIa most directly causes which change? A. Disk-to-sphere transformation | back 17 A. Disk-to-sphere transformation |
front 18 Binding of subendothelial vWF to platelet GPIb most directly exposes binding sites for: A. Collagen and thrombin | back 18 D. Fibrinogen and vWF |
front 19 An inherited mutation in platelet GPIb causes which disorder? A. Glanzmann thrombasthenia | back 19 B. Bernard-Soulier syndrome |
front 20 Familial TTP is most closely associated with mutation of which enzyme? A. Platelet cyclooxygenase | back 20 C. vWF-specific metalloprotease |
front 21 ADP released from activated platelets most directly promotes further exposure of: A. GPIIb/IIIa binding sites | back 21 A. GPIIb/IIIa binding sites |
front 22 The α and β peptides of fibrinogen are held together primarily by: A. Ionic interactions | back 22 D. Disulfide bonds |
front 23 A patient has an isolated defect in a coagulation enzyme class shared by factors VII, IX, X, XI, and prothrombin. Which class is affected? A. Serine proteases | back 23 A. Serine proteases |
front 24 Which pair functions primarily as cofactor binding proteins within the coagulation cascade? A. II and X | back 24 D. V and VIII |
front 25 In response to collagen and thrombin, activated platelets release which prominent vasoconstrictor pair? A. ADP and fibrinogen | back 25 B. Serotonin and thromboxane A2 |
front 26 A patient forms unstable clots that fail to become covalently cross-linked. Which factor normally acts as a Ca2+-dependent transglutaminase? A. Factor V | back 26 C. Factor XIII |
front 27 Which sequence best describes the key steps of the extrinsic pathway? A. VII binds tissue factor, activates X | back 27 A. VII binds tissue factor, activates X |
front 28 During fibrin stabilization, factor XIIIa catalyzes which reaction between fibrin monomers? A. Hydrolysis of lysine-serine bonds | back 28 C. Transamidation of glutamine and lysine |
front 29 Which activated coagulation factor is the only enzyme in the cascade that is not a serine protease? A. Factor XIIIa | back 29 A. Factor XIIIa |
front 30 A patient on a vitamin K antagonist will produce reduced amounts of which gamma-carboxylated factor set? A. V, VIII, XI, XIII | back 30 C. II, VII, IX, X |
front 31 Gamma-carboxyglutamate residues allow certain factors to form coordination complexes with Ca2+. Which pair is specifically listed? A. Factor VII and IX | back 31 B. Factor X and prothrombin |
front 32 Warfarin most directly impairs gamma-carboxylation of which anticoagulant pair in addition to clotting factors? A. Protein C and protein S | back 32 A. Protein C and protein S |
front 33 A mutation disrupts assembly of the prothrombinase complex by altering a cofactor that binds Xa and prothrombin. Which factor is affected? A. Factor VIIIa | back 33 C. Factor Va |
front 34 Vitamin K is functionally active in which chemical form? A. Quinone form | back 34 B. Hydroquinone form |
front 35 The enzyme targeted by warfarin is best identified as: A. Vitamin K epoxide reductase | back 35 A. Vitamin K epoxide reductase |
front 36 Which group is activated by thrombin in its prothrombotic regulatory role? A. II, VII, X | back 36 C. V, VIII, XI |
front 37 Which action directly promotes clot formation by thrombin? A. Activating plasmin from plasminogen | back 37 B. Cleaving factor XIII to XIIIa |
front 38 Thrombin produces antithrombotic effects after binding to: A. von Willebrand factor | back 38 D. Thrombomodulin |
front 39 Binding of thrombin to thrombomodulin leads to activation of which anticoagulant? A. Protein S | back 39 B. Protein C |
front 40 A neonate with a homozygous defect dies early from severe thrombotic disease. Deficiency of which pair is most consistent with this presentation? A. Factors V and VIII | back 40 C. Protein C and protein S |
front 41 The activated protein C complex exerts anticoagulant effects by destroying which factors? A. Va and VIIIa | back 41 A. Va and VIIIa |
front 42 A patient with inherited thrombophilia has factor V Leiden. Which amino acid substitution is classically present? A. Glycine to serine | back 42 D. Arginine to glutamine |
front 43 A young adult with inherited thrombophilia develops a postoperative leg clot. Which condition is most strongly associated with Factor V Leiden? A. Deep venous thrombosis | back 43 A. Deep venous thrombosis |
front 44 Activity of thrombin is primarily restrained by which serpin? A. Protein C | back 44 B. Antithrombin III |
front 45 Formation of the antithrombin III-thrombin complex involves which residue pair? A. Serine on thrombin | back 45 A. Serine on thrombin |
front 46 Formation of the antithrombin III-thrombin complex involves which residue pair? (second pair) A. Lysine on antithrombin | back 46 B. Arginine on antithrombin |
front 47 Heparin accelerates antithrombin III activity by binding primarily to which residue on antithrombin III? A. Lysine | back 47 A. Lysine |
front 48 The antithrombin III-heparin complex can directly inactivate which factor? A. Factor VIIa | back 48 D. Factor Xa |
front 49 Which coagulation-related protein is not inactivated by the antithrombin III-heparin complex? A. Factor IXa | back 49 C. Factor VIIa |
front 50 Healthy endothelial cells reduce platelet aggregation by synthesizing which pair? A. TXA2 and serotonin | back 50 B. PGI2 and nitric oxide |
front 51 Which enzyme directly cleaves fibrin during fibrinolysis? A. Plasmin | back 51 A. Plasmin |
front 52 In addition to suppressing coagulation, activated protein C promotes fibrinolysis by stimulating release of: A. Thrombomodulin | back 52 C. Tissue plasminogen activator |
front 53 Circulating plasmin is rapidly neutralized by which inhibitor? A. Alpha-1 antitrypsin | back 53 B. Alpha-2 antiplasmin |
front 54 A boy with hemarthroses has classic hemophilia A. Which factor is deficient? A. Factor IX | back 54 B. Factor VIII |
front 55 A patient with hemophilia B most likely has a mutation in which factor? A. Factor V | back 55 C. Factor IX |
front 56 A point mutation R98W in VKORC1 is associated with which disorder? A. Hemophilia B | back 56 D. VKCFD2 |
front 57 Clopidogrel and ticagrelor inhibit platelet aggregation by blocking which receptor? A. GPIIb/IIIa receptor | back 57 C. P2Y12 receptor |
front 58 A patient with severe hypoalbuminemia develops dependent edema despite normal cardiac function. Which plasma protein role is most directly impaired? A. Maintaining plasma oncotic pressure | back 58 A. Maintaining plasma oncotic pressure |
front 59 A patient with thrombocytopenia continues to ooze from a small vascular injury. Which normal platelet function is most immediately lost? A. Mechanical plug formation | back 59 A. Mechanical plug formation |
front 60 Platelets become activated after binding to a site of vascular injury. What is the most important immediate consequence? A. Reduced local vasoconstriction | back 60 B. Increased platelet aggregation |
front 61 At the site of endothelial injury, circulating fibrinogen most directly binds to: A. Resting erythrocyte membranes | back 61 B. Activated platelets |
front 62 Normal hemostasis requires tight regulation of clotting primarily to prevent: A. Polycythemia and leukopenia | back 62 B. Thrombosis and bleeding |
front 63 The clotting cascade is best described as a sequence of events leading to activation of: A. Plasmin | back 63 C. Thrombin |
front 64 A patient has impaired conversion of fibrinogen into fibrin during clot formation. Which enzyme is most directly deficient? A. Thrombin | back 64 A. Thrombin |
front 65 A newly formed soft clot fails to become a stable hard clot. Which thrombin-dependent process is most likely defective? A. Platelet serotonin release | back 65 B. Fibrin cross-linking |
front 66 Proteins C and S act together to regulate coagulation after being activated by: A. Fibrinogen | back 66 C. Thrombin |
front 67 To assemble clotting complexes on activated platelets, certain factors require gamma-carboxyglutamate residues primarily to bind: A. Sodium and fibrin | back 67 B. Calcium and membranes |
front 68 Antithrombin III is best classified as which type of regulatory molecule? A. Serine protease inhibitor | back 68 A. Serine protease inhibitor |
front 69 Which protease is uniquely capable of dissolving an established fibrin clot? A. Thrombin | back 69 C. Plasmin |
front 70 A boy with recurrent hemarthroses is missing an essential factor for thrombin activation. Which diagnosis best fits? A. Hemophilia A | back 70 A. Hemophilia A |