MCQ Hematology Answer 38

The correct answer is A.

Fibrinogen is cleaved by thrombin twice as it is activated to form fibrin. The initial cleavage causes it to polymerize and the second causes it to branch. Thrombin also activates Factor XIII to XIIIa, which crosslinks the fibrin strands and strengthens the clot.

HMWK (choice B) is a cofactor in the intrinsic pathway that converts Factor XI to XIa.

Plasminogen (choice C) is a central proenzyme in clot lysis. When plasminogen is converted to plasmin, it digests fibrin threads, as well as a number of protein factors including Factors V, VIII, XII, and prothrombin.

Thrombin (choice D) is an enzyme derived from prothrombin. It converts fibrinogen to fibrin, and activates factor XIII.

Category: Hematology MCQs