Question

Which acid renders the acidic pH in stomach for the activity of protein digesting enzymes?

• A. HCl
• B. H\(_2\)SO\(_4\)
• C. HNO\(_3\)
• D. HCO\(_3^{}\)

Hint:

Stomach Acidity.

• HCl lowers stomach pH.
• Activates pepsin.
• Kills microbes and denatures proteins.

Answer 1

The Correct Option is A

Hydrochloric acid (HCl), secreted by parietal cells in the gastric glands, is responsible for maintaining the stomach's acidic pH (around 1.5–3.5). This acidic environment is essential for activating pepsinogen into pepsin, a key protein-digesting enzyme. Other acids listed are either not found in the human body or serve different functions.

Answer 2

The acid responsible for rendering the acidic pH in the stomach is Hydrochloric acid (HCl).
HCl is secreted by the parietal cells of the stomach lining and plays a vital role in digestion.
The acidic environment created by HCl, with a pH around 1.5 to 3.5, is essential for the activation and optimal functioning of protein-digesting enzymes like pepsin.
Pepsinogen, an inactive enzyme secreted by chief cells, is converted into its active form pepsin in the presence of HCl.
This acidic condition also helps in breaking down the food particles, denaturing proteins and killing harmful bacteria and pathogens ingested with food.
Additionally, HCl facilitates the absorption of certain nutrients and minerals such as iron and calcium.
Without sufficient HCl, protein digestion would be inefficient, leading to digestive issues.
Thus, hydrochloric acid is indispensable for proper digestion and maintaining the stomach's health.
Its secretion and regulation are tightly controlled by the nervous system and hormones to ensure digestive balance.
In summary, HCl creates the acidic medium necessary for protein digestion and protects the body from ingested microbes.