Given below is a diagram of a human blood smear. Study the diagram and answer the questions that follow: Given below is a diagram of a human blood smear. Study the diagram and answer the questions that follow:
Name the soluble protein found in part ‘4’ which forms insoluble threads during clotting of blood.
Topic: Fibrinogen
Answer
FIBRINOGEN.
FIBRINOGEN is a soluble plasma protein. During clotting, the enzyme THROMBIN converts it into insoluble FIBRIN, whose threads form a mesh across the wound, trapping blood cells and sealing it.
THE CLOTTING SEQUENCE, since any step may be asked: platelets release THROMBOPLASTIN thromboplastin, with CALCIUM and vitamin K, converts PROTHROMBIN into THROMBIN thrombin converts soluble FIBRINOGEN into insoluble FIBRIN
NOTE THE PAIRS: prothrombin → thrombin, fibrinogen → fibrin. In each case the longer name is the INACTIVE precursor and the shorter the ACTIVE form.
A failure anywhere in this chain causes HAEMOPHILIA.