Protochlorophyll differs from chlorophyll in lacking

Options

A. 2 hydrogen atoms in two of its pyrrole rings
B. 2 hydrogen atoms in one of its pyrrole rings
C. 4 hydrogen atoms in one of its pyrrole rings
D. 4 hydrogen atoms in two of its pyrrole rings

Explanation

**Step-by-Step Solution:**

1. **Understanding Chlorophyll and Protochlorophyll:**
- Chlorophyll is a green pigment essential for photosynthesis, allowing plants to capture light energy.
- Protochlorophyll is a precursor to chlorophyll, which forms when seedlings are grown in the dark.

2. **Identifying the Structural Differences:**
- Both chlorophyll and protochlorophyll have a similar structure, but they differ in the number of hydrogen atoms present in their pyrrole rings.

3. **Analyzing the Options:**
- The question provides four options regarding the difference in hydrogen atoms between protochlorophyll and chlorophyll:
a. Two hydrogen atoms in two of its spiral rings
b. Two hydrogen atoms in one of its spiral rings
c. Four hydrogen atoms in one of its spiral rings
d. Four hydrogen atoms in two of its spiral rings

4. **Finding the Correct Option:**
- The key difference is that protochlorophyll lacks two hydrogen atoms in one of its pyrrole rings compared to chlorophyll.
- Therefore, the correct answer is **option B: two hydrogen atoms in one of its pyrrole rings.**

5. **Conclusion:**
- Protochlorophyll differs from chlorophyll specifically in the absence of two hydrogen atoms in one of its pyrrole rings, which is critical for its function and formation.