How does pepsinogen change into its active form ?

Options

A. It is converted into pepsin by hydrochloric acid
B. It is converted into pepsin by sodium bicarbonate
C. it is converted into pepsin by hydrogen per oxide
D. It is converted into pepsin by trypsin

Answer

### Step-by-Step Solution:

1. **Understanding Pepsinogen**: Pepsinogen is an inactive precursor (zymogen) of the enzyme pepsin. It is secreted by the gastric glands in the stomach lining.

2. **Role of Hydrochloric Acid**: When food enters the stomach, the gastric glands secrete hydrochloric acid (HCl). This acid creates an acidic environment in the stomach, which is essential for the activation of pepsinogen.

3. **Conversion to Pepsin**: In the presence of hydrochloric acid, pepsinogen undergoes a conformational change. The acidic environment causes pepsinogen to lose a small peptide fragment, resulting in the formation of the active enzyme, pepsin.

4. **Function of Pepsin**: Once activated, pepsin begins to break down proteins into smaller peptides. This process is crucial for protein digestion and ultimately leads to the formation of amino acids.

5. **Absorption of Amino Acids**: The amino acids produced from protein digestion are then absorbed in the small intestine and utilized by the body for various functions, including growth and repair.