Which of the following is present in the saliva of all mammals?

Options

A. Mucin
B. Salivary amylase
C. Diastase
D. Amylopsin

Answer

To determine which component is present in the saliva of all mammals, we can analyze the options provided:

1. **Understanding the Options**:
- **Mucin**: A high molecular weight glycoprotein that serves as a lubricant and protective agent in saliva.
- **Salivary Amylase**: An enzyme that breaks down carbohydrates into sugars, present in the saliva of many mammals but not all.
- **Diastase**: A term that refers to a group of enzymes that catalyze the breakdown of starch into maltose; not specifically present in all mammalian saliva.
- **Amylopsin**: An enzyme found in pancreatic juice, not in saliva.

2. **Analyzing Mucin**:
- Mucin is produced by epithelial cells and is found in the saliva of all mammals. It plays a crucial role in lubrication and protection against microbes and physical damage.

3. **Analyzing Salivary Amylase**:
- While salivary amylase is a common enzyme in many mammals, it is not universally present in all species.

4. **Analyzing Diastase and Amylopsin**:
- Diastase is a general term for enzymes that break down starch, but it is not specifically present in all mammalian saliva.
- Amylopsin is not found in saliva; it is part of pancreatic juice.

5. **Conclusion**:
- The only component that is universally present in the saliva of all mammals is **mucin**.

Thus, the correct answer is **mucin**.