Question

Which prevents the conversion of prothrombin to thrombin in an undamaged blood vessel?
A. Thromboplastin
B. Fibrinogen
C. Heparin
D. Calcium

Answer 1

Hint: During blood clotting, prothrombin is converted into thrombin with the help of thrombokinase and calcium ions. Heparin is an anticoagulant, which prevents the conversion of prothrombin into thrombin.

Complete answer: Prothrombin is transformed into thrombin by a clotting factor known as factor X or prothrombinase; thrombin then acts to transform fibrinogen, also present in plasma, into fibrin, which, in combination with platelets from the blood, forms a clot (a process called coagulation).
Anticoagulants such as heparin or warfarin (also called Coumadin) slow down your body's process of making clots.
Antiplatelet drugs, such as aspirin, prevent blood cells called platelets from clumping together to form a clot.
When you take a blood thinner, follow directions carefully.

So, the right answer is option C. Heparin.

Note: Anticoagulants are medicines that help prevent blood clots.
They're given to people at a high risk of getting clots, to reduce their chances of developing serious conditions such as strokes and heart attacks.
A blood clot is a seal created by the blood to stop bleeding from wounds.