Question

Which of the following statements is incorrect?

• A. Fibrinogen is produced from fibrin
• B. Blood coagulates in response to an injury
• C. Blood clot consists of fibrins
• D. Fibrin is produced from fibrinogen

Hint:

Remember the blood clotting conversion sequence as: Fibrinogen (soluble) $\rightarrow$ Fibrin (insoluble clot fibers). If reversed in options, it is incorrect.

Answer 1

The Correct Option is A

Concept: Blood coagulation or blood clotting is an extremely important protective mechanism of the human body. Whenever an injury causes damage to blood vessels, the body activates a sequence of biochemical reactions known as the clotting cascade. This process prevents excessive blood loss. A protein called fibrinogen, which is soluble in blood plasma, gets converted into an insoluble protein called fibrin by the action of the enzyme thrombin. These fibrin threads form a mesh-like network that traps blood cells and ultimately forms the blood clot. To answer this question, we need to understand the direction of conversion between fibrinogen and fibrin and identify which statement incorrectly represents this biological process.

Step 1: Understand the role of fibrinogen in blood clotting.
Fibrinogen is a soluble plasma protein present in circulating blood. It remains inactive under normal physiological conditions. When tissue damage occurs, clotting factors become activated and eventually convert prothrombin into thrombin. Thrombin then acts on fibrinogen and converts it into fibrin. Thus, the biological pathway is \[ Fibrinogen \rightarrow Fibrin \] and not the reverse process.

Step 2: Check Option (A).
Option (A) states Fibrinogen is produced from fibrin This is scientifically incorrect. Fibrinogen is the precursor molecule and fibrin is produced from fibrinogen during coagulation. Hence this statement reverses the actual biological process. Therefore option (A) is incorrect.

Step 3: Verify the remaining options.
Option (B): Blood coagulates in response to injury. This is correct because clotting is a defense mechanism activated during vascular injury. Option (C): Blood clot consists of fibrins. This is correct because fibrin forms thread-like fibers making the clot mesh. Option (D): Fibrin is produced from fibrinogen. This is biologically correct.

Step 4: Determine final answer.
Since only Option (A) contradicts the actual blood clotting mechanism, it is the incorrect statement. Hence, \[ \boxed{\text{Option (1)}} \]