Just as hydrochloric acid is for pepsinogen, so is the :

Options

A. haemoglobin to oxygen
B. enterokinase to typsinogen
C. bile juice to fat
D. glucagon to glycongen

Answer

To solve the question "Just as hydrochloric acid is for pepsinogen, so is the:", we need to identify the correct analogy based on the activation of enzymes.

### Step-by-Step Solution:

1. **Understanding Pepsinogen Activation**:
- Pepsinogen is an inactive enzyme (zymogen) that is converted into its active form, pepsin, in the presence of hydrochloric acid (HCl) in the stomach. This process is crucial for protein digestion.

2. **Identifying the Options**:
- We need to analyze the options provided in the question to find an analogous relationship where an inactive enzyme is activated by a specific factor.

3. **Evaluating Each Option**:
- **Option 1: Hemoglobin to Oxygen**:
- This option is incorrect because hemoglobin does not activate oxygen; it simply carries it in the blood.

- **Option 2: Enterokinase to Trypsinogen**:
- This option is correct. Enterokinase is an enzyme produced in the intestine that activates trypsinogen (another inactive enzyme) into trypsin. This is similar to how HCl activates pepsinogen.

- **Option 3: Bile Juice to Fat**:
- This option is incorrect. Bile juice emulsifies fats but does not activate any enzymes.

- **Option 4: Glucagon to Glycogen**:
- This option is also incorrect. Glucagon is a hormone that promotes the breakdown of glycogen into glucose, but it does not activate an enzyme.

4. **Conclusion**:
- The correct analogy is that just as hydrochloric acid activates pepsinogen, enterokinase activates trypsinogen.

### Final Answer:
Just as hydrochloric acid is for pepsinogen, so is enterokinase for trypsinogen.

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