A soluble clotting factor that is made insoluble by thrombin is ………….

Options

A. prothrmbin
B. fibrinogen
C. fibrin
D. calcium ions

Answer

To answer the question, "A soluble clotting factor that is made insoluble by thrombin is ………….," we can follow these steps:

### Step 1: Understand the Role of Clotting Factors
Clotting factors are proteins in the blood that help control bleeding. When a blood vessel is injured, these factors work together in a complex cascade to form a clot.

### Step 2: Identify the Soluble Clotting Factors
Among the various clotting factors, fibrinogen is a soluble protein found in plasma. It plays a crucial role in the clotting process.

### Step 3: The Role of Thrombin
Thrombin is an enzyme that converts fibrinogen into fibrin, which is an insoluble protein. This conversion is essential for the formation of a stable blood clot.

### Step 4: Analyze the Options
- **Prothrombin**: This is an inactive precursor to thrombin, not a soluble clotting factor that becomes insoluble.
- **Fibrinogen**: This is the correct answer, as it is soluble and is converted to insoluble fibrin by thrombin.
- **Fibrins**: This refers to the insoluble form after conversion and is not a soluble factor.
- **Calcium ions**: These are important for the clotting process but are not a clotting factor themselves.

### Step 5: Conclusion
The soluble clotting factor that is made insoluble by thrombin is **Fibrinogen**.

### Final Answer
**Fibrinogen**

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