Question

The initial step in the digestion of milk in humans is carried out by the enzyme \( \text{Renin (Rennin)} \).

• A. Trypsin
• B. Rennin
• C. Pepsin
• D. Lipase

Answer 1

The Correct Option is B

The question asks about the initial step in the digestion of milk in humans. To answer this, we need to understand the role of various enzymes in the digestive process.

Milk digestion primarily involves breaking down its protein and fat content. The key proteins in milk are casein and whey proteins. Let's explore the enzymes mentioned in the options:

1. Trypsin: This enzyme is produced in the pancreas and acts in the small intestine. It primarily helps in the digestion of peptides. It is not involved in the initial digestion of milk.
2. Rennin: This is the correct answer. Rennin, also known as chymosin, is an enzyme produced in the stomachs of infants. It plays a crucial role in curdling milk by converting soluble caseinogen into insoluble casein, forming a curd. This makes it easier for milk proteins to be further digested by other enzymes.
3. Pepsin: This is another enzyme that operates in the stomach and aids in protein digestion. While it contributes to protein breakdown, pepsin is more general and does not specifically initiate the digestion of milk proteins.
4. Lipase: This enzyme is responsible for breaking down fats into fatty acids and glycerol and is not involved in the initial digestion of milk protein.

Given the roles of these enzymes, Rennin is the enzyme specifically responsible for the initial step of digesting milk by curdling it, especially significant in infants. Thus, Rennin is the correct answer.