Question

After a wound occurs, several processes that help in blood clotting are initiated.
(a) Which enzyme initiates these reactions?
(b) Explain how the activity of this enzyme helps the clotting mechanism.

Hint:

Remember: Prothrombin → Thrombin → Fibrinogen → Fibrin → Clot formation.

Answer 1

Step 1: Identify the initiating enzyme.
When a wound occurs, the clotting process begins with the activation of an enzyme called thrombin.
Step 2: Understand the precursor activation.
Thrombin is formed from its inactive precursor prothrombin in the presence of clotting factors such as calcium ions and thromboplastin released from damaged tissues.
Step 3: Role of thrombin in clotting.
Thrombin plays a crucial role by converting the soluble plasma protein fibrinogen into insoluble fibrin threads.
Step 4: Formation of clot.
These fibrin threads form a mesh-like network that traps blood cells such as red blood cells and platelets, leading to the formation of a blood clot.
Step 5: Final outcome.
The clot seals the wound, preventing further blood loss and protecting the body from infection.