Which one of the following enzymes carries out the initial step in the digestion of milk in humans?

Options

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

Answer

To solve the question about which enzyme carries out the initial step in the digestion of milk in humans, we can follow these steps:

### Step 1: Understand the Question
The question is asking for the enzyme responsible for the initial digestion of milk in humans.

### Step 2: Review the Options
The options provided are:
- Trypsin
- Renin
- Pepsin
- Lipase

### Step 3: Analyze Each Enzyme
- **Trypsin**: This enzyme is a protease that digests proteins and is secreted in the small intestine. It does not play a role in the initial digestion of milk.

- **Renin**: This enzyme is secreted in the stomach and is involved in the hydrolysis of casein (a milk protein) into paracasein. It is important for milk digestion in infants, but not the primary enzyme in adults.

- **Pepsin**: This is a proteolytic enzyme that digests proteins in the stomach. It is involved in breaking down protein structures but is not specifically known for milk digestion.

- **Lipase**: This enzyme is responsible for the digestion of fats. While it is important in lipid digestion, it is not the primary enzyme for the initial digestion of milk.

### Step 4: Identify the Correct Answer
Based on the analysis, **Renin** is the enzyme that carries out the initial step in the digestion of milk in humans, particularly in infants. It acts on casein to form paracasein, which is crucial for milk digestion.

### Conclusion
The correct answer to the question is **Renin**.

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