Which is not a function of HCl ?

Options

A. Killing microbes
B. Prevention of food decay
C. Solubilisation of calcified hard parts
D. Stimulation of lipase in stomach

Answer

To determine which option is not a function of hydrochloric acid (HCl) in the stomach, we will analyze each of the provided options step by step.

### Step 1: Understand the Role of HCl in the Stomach
Hydrochloric acid is secreted by the parietal cells in the stomach and plays several important roles in digestion.

### Step 2: Evaluate Each Option
1. **Killing Microbes**: HCl creates a highly acidic environment (pH less than 3) in the stomach, which is hostile to many microbes. This function helps in killing harmful bacteria and pathogens that may be ingested with food. **(This is a function of HCl.)**

2. **Prevention of Food Decay**: By killing microbes, HCl also helps prevent the decay of food. The acidic environment inhibits the growth of bacteria and other microorganisms that cause food spoilage. **(This is a function of HCl.)**

3. **Solubilization of Calcified Hard Parts**: HCl aids in the digestion of harder food components, such as cartilage in meat, by solubilizing calcified parts. This is particularly important in carnivorous animals. **(This is a function of HCl.)**

4. **Stimulation of Lipase in the Stomach**: Lipase is an enzyme that helps in the digestion of fats. However, its stimulation is not directly caused by HCl. Instead, lipase is stimulated by the presence of fats and the hormone gastrin. **(This is NOT a function of HCl.)**

### Conclusion
The option that is not a function of HCl is **stimulation of lipase in the stomach**.

### Final Answer
**Stimulation of lipase in the stomach is not a function of HCl.**

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