Phytochrome is a

Options

A. flavoprotein
B. glycoprotein
C. lipoprotein
D. chromoprotein

Answer

**Step-by-Step Solution:**

1. **Understanding Phytochrome**: Phytochrome is a photoreceptor protein that plants use to detect light. It plays a crucial role in regulating various aspects of plant growth and development, including flowering, seed germination, and shade avoidance.

2. **Evaluating Options**: The question provides multiple-choice answers regarding what phytochrome is. We need to analyze each option to determine which one correctly describes phytochrome.

3. **Option Analysis**:
- **Option 1**: States that phytochrome is a type of protein that contains a nucleic acid derivative of riboflavin. This is incorrect as phytochrome does not contain a nucleic acid derivative.
- **Option 2**: Describes phytochrome as a glycoprotein. Glycoproteins are proteins that have carbohydrate chains attached, which is not the case for phytochrome.
- **Option 3**: Identifies phytochrome as a lipoprotein. Lipoproteins are complexes of lipids and proteins, which does not apply to phytochrome.
- **Option 4**: States that phytochrome is a chromoprotein. Chromoproteins are proteins that contain a pigmented prosthetic group, which is indeed true for phytochrome as it contains a chromophore that absorbs light.

4. **Conclusion**: Based on the analysis, the correct answer is Option 4: Phytochrome is a chromoprotein that plays a significant role in regulating flowering and other growth processes in plants.