Question

Read the statements given below and choose the correct sequence of events leading the formation of a blood clot.
(i) Calcium activates an enzyme.
(ii) Fibrin binds platelets to form a 'plug'.
(iii) Thrombin converts fibrinogen to fibrin.
(iv) Platelets and damaged cells release an activator.

• A. (i), (ii), (iii), (iv)
• B. (ii), (i), (iii), (iv)
• C. (iii), (iv), (i), (ii)
• D. (iv), (i), (iii), (ii)

Answer 1

The correct option is D (iv), (i), (iii), (ii)

The process of blood clotting starts with the release of thromboplastin from damaged cells and platelets. Thromboplastin converts plasma protein prothrombin into thrombin in the presence of calcium ions. Thrombin then converts soluble plasma protein fibrinogen into fibrin which binds platelets to form a clot.

Therefore, the correct answer is option D.