Red algae show maximum photosynthesis in blue green light. Their main pigment to trap this light is

Options

A. chlorophyll
B. phycoerythrin
C. chl a and xanthophyll
D. carotenes.

Answer

To solve the question regarding the main pigment in red algae that allows them to perform maximum photosynthesis in blue-green light, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Red Algae**:
- Red algae belong to the group known as Rhodophyceae. They are characterized by their unique pigments that allow them to thrive in deeper waters where blue-green light predominates.

2. **Identifying the Pigments**:
- Red algae contain several pigments, including chlorophylls (A to D) and phycoerythrin. Each of these pigments has a specific role in photosynthesis and light absorption.

3. **Analyzing the Options**:
- The options provided are:
- A) Chlorophyll
- B) Phycoerythrin
- C) Chlorophyll-a
- D) Xanthophyll and Carotenes

4. **Evaluating Each Option**:
- **Chlorophyll**: While chlorophyll is present in all types of algae, it is not the main pigment for red algae in blue-green light.
- **Phycoerythrin**: This pigment is specifically found in red algae and is known to absorb blue-green light effectively, making it the primary pigment for photosynthesis in these organisms.
- **Chlorophyll-a**: This is a type of chlorophyll but is not the main pigment responsible for maximum photosynthesis in red algae.
- **Xanthophyll and Carotenes**: These are accessory pigments that assist in photosynthesis but are not the main pigments for red algae.

5. **Conclusion**:
- Based on the analysis, the main pigment that allows red algae to perform maximum photosynthesis in blue-green light is **phycoerythrin**.

### Final Answer:
The main pigment in red algae that traps blue-green light for maximum photosynthesis is **phycoerythrin**.

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