Identify the acid that helps in digestion.

Hydrochloric acid

The correct answer is option 3. Hydrochloric acid.

Hydrochloric acid (HCl) is the acid that helps in digestion.

Hydrochloric acid is produced by the parietal cells in the lining of the stomach. These cells secrete HCl in response to signals such as the presence of food in the stomach or hormonal stimulation.

The secretion of hydrochloric acid creates an acidic environment in the stomach, with a pH ranging from approximately 1.5 to 3.5. This highly acidic environment is crucial for the digestion of food.

One of the primary functions of hydrochloric acid is to activate pepsinogen, an inactive enzyme secreted by the chief cells in the stomach. HCl converts pepsinogen into its active form, pepsin, which is a protease enzyme responsible for breaking down proteins into smaller peptides.

Hydrochloric acid also plays a role in the denaturation of proteins. It unfolds the complex three-dimensional structure of dietary proteins, making them more accessible to the action of digestive enzymes like pepsin.

The acidic pH environment created by hydrochloric acid in the stomach provides an optimal pH for the activity of pepsin and other digestive enzymes involved in protein digestion.

The low pH of hydrochloric acid also helps to kill ingested bacteria and other pathogens, reducing the risk of infections from foodborne pathogens.

In summary, hydrochloric acid plays a crucial role in the digestive process by creating an acidic environment in the stomach, activating pepsin for protein digestion, denaturing dietary proteins, and aiding in the destruction of ingested pathogens. It is essential for breaking down food into smaller molecules that can be absorbed and utilized by the body.