Plasma proteins involved in the coagulation of blood

The correct answer is option 'D' - fibrinogen.

Explanation:

Blood coagulation is a complex process that involves the conversion of soluble fibrinogen into insoluble fibrin, forming a clot to stop bleeding. This process is mediated by several plasma proteins known as clotting factors.

Fibrinogen:
- Fibrinogen is a soluble plasma protein and is one of the key components involved in blood coagulation.
- It is produced by the liver and released into the bloodstream.
- Fibrinogen plays a crucial role in the final step of blood coagulation, where it is converted into fibrin.
- Fibrinogen contains specific regions that can bind to activated platelets and other clotting factors, facilitating the formation of a stable blood clot.

Other plasma proteins:
a) Albumin:
- Albumin is the most abundant plasma protein and has various functions, including maintaining osmotic pressure and transporting substances.
- It is not directly involved in the coagulation process.

b) Serum amylase:
- Serum amylase is an enzyme that helps in the digestion of carbohydrates.
- It is not involved in blood coagulation.

c) Globulin:
- Globulin is a general term for a group of proteins present in the blood.
- It includes various types, such as alpha, beta, and gamma globulins, which have different functions.
- While some globulins may have a minor role in blood coagulation, they are not directly involved in the process.

Conclusion:
Among the given options, the plasma protein involved in the coagulation of blood is fibrinogen. Fibrinogen is converted into insoluble fibrin, which forms a blood clot. The other options, such as albumin, serum amylase, and globulins, do not directly participate in the coagulation process.