Question

Thrombokinase is associated with -
(a) Elimination of urea and other excretory products from the body
(b) Production of erythrocytes from the bone marrow
(c) Pulmonary and systemic circulation
(d) Cardiac cycle and it’s regulation
(e) Enzymatic reactions in the coagulation of blood

Answer 1

Hint: Thrombokinase is an enzyme that works in conjunction with platelets. It is used for activating another enzyme that is responsible for a process in the body. Hence, it is produced in a process where platelets are specifically required.

Complete step by step answer:
- Thrombokinase is an enzyme present in blood platelets and it converts prothrombin into thrombin. The enzyme aids in the process of blood clotting.
- When a blood vessel is injured, it releases thrombokinase. This along with various factors released by the platelets convert prothrombin to thrombin, which is the inactive and active form of the enzyme, respectively.
- Thrombin converts fibrinogen, a plasma protein, into fibrin, an insoluble protein in the form of insoluble fibers. These fibers form a mesh network, trapping the RBCs and preventing their loss from the site of injury. This ultimately forms a blood clot and remains until the injury is healed.
- Thrombokinase is also known as thromboplastin.
- Antidiuretic hormone/Vasopressin is the hormone responsible for regulating the reabsorption of water in kidneys and therefore the volume of urine in excretion.
- Production of erythrocytes requires the hormone erythropoietin, and substrates such as iron, vitamin ${B12}$, folate, and heme.
- Pulmonary and systemic circulation and the cardiac cycle work in harmony to circulate oxygen throughout the body through hemoglobin in the blood.
So, the correct answer is ‘(e) Enzymatic reactions in the coagulation of blood’.

Note:
- Failure of any steps in blood clotting leads to hemorrhage or excessive bleeding that can lead to death.
- Substances that oppose the formation of a blood clot are known as anticoagulants and are consumed to dissolve blood clots and in the prevention of strokes and heart attacks in susceptible patients.