Question

prothrombinase is formed in the presence of 1.ca++ 2.mg++ 3.fe++ 4.fe+++

Answer 1

The question is incorrect. The correct question along with its solution is given below:

Correct Question:

Thrombin is formed in the presence of:

1. Ca²⁺
2. Mg²⁺
3. Fe²⁺
4. Fe³⁺

Answer:

Thrombin is formed from prothrombin in the presence of Ca²⁺ ions.

Explanation:

Mechanism of Coagulation of Blood:

In the event of an injury, blood oozes out of the wound. But eventually, after some time, the blood seizes to flow. The mechanism involved in this stoppage of the flow of blood from the wound is known as coagulation of blood. The clot or coagulum is basically a network of fine threads called fibrins in which the damaged formed elements are entrapped.

The process of coagulation involves an involvement of many 'factors' which eventually remain in their inactive state, and are activated as soon as the body suffers an injury or trauma.

The events which lead to coagulation post-injury are highlighted below in a step-by-step manner:

1. The injury stimulates the platelets (and also the tissues surrounding the area of the injury) to release thromboplastins.
2. The thromboplastins undergo a series of enzymatic step-by-step reactions (popularly referred to as the cascade process) that lead to the formation of an enzyme complex known as thrombokinase.
3. The thrombokinase acts as an enzyme which converts inactive prothrombin present in the plasma into active thrombin in presence of Ca²⁺ ions.
4. This thrombin, again in the presence of Ca²⁺ ions, converts inactive fibrinogen into active fibrin.
5. This fibrin forms a network of fine threads that entrap the damaged formed elements to form a blood clot. The clot seals the damaged blood vessel and stops bleeding.

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