Action spectrum of photosynthesis corresponds closely to absorption spectrum of

Options

A. Cholorophyll a
B. Chlorophyll b
C. Carotene
D. Xanthophyll

Answer

To solve the question regarding which pigment's absorption spectrum corresponds closely to the action spectrum of photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Absorption Spectrum**: This refers to the specific wavelengths of light that a pigment absorbs. Each pigment has a unique absorption spectrum that indicates which wavelengths are absorbed and which are reflected.
- **Action Spectrum**: This represents the rate of photosynthesis at different wavelengths of light. It shows which wavelengths are most effective for photosynthesis.

2. **Identify the Key Pigments**:
- The main pigments involved in photosynthesis are chlorophyll A, chlorophyll B, carotene, and xanthophyll. Each of these pigments has a different absorption spectrum.

3. **Compare the Spectra**:
- Chlorophyll A is the primary pigment in photosynthesis and is known to absorb light most effectively in the blue and red wavelengths.
- Chlorophyll B assists chlorophyll A by capturing light energy and has a slightly different absorption spectrum, but it is still closely related to chlorophyll A.
- Carotene and xanthophyll are accessory pigments that absorb light in different wavelengths but do not play as significant a role in the overall photosynthesis process.

4. **Determine the Closest Match**:
- When comparing the absorption spectrum of chlorophyll A with the action spectrum of photosynthesis, it is found that they correspond closely. Chlorophyll A is primarily responsible for the light reactions of photosynthesis, making its absorption spectrum align well with the action spectrum.

5. **Conclusion**:
- Based on the analysis, the pigment whose absorption spectrum corresponds closely to the action spectrum of photosynthesis is **Chlorophyll A**.

### Final Answer:
The action spectrum of photosynthesis corresponds closely to the absorption spectrum of **Chlorophyll A**.