SSC CPO 2025 PYQ — Question 47

Answer: (A) Chlorophyll a

Explanation –

Chlorophyll a is the primary photosynthetic pigment found in plants. It is present in all oxygen-evolving photosynthetic organisms (plants, algae, and cyanobacteria). Chlorophyll a primarily absorbs light in the blue-violet and red wavelengths, while reflecting green light; this is why plants appear green.

This pigment is directly responsible for converting light energy into chemical energy. Although chlorophyll b and carotenoids also absorb light, they function as accessory pigments and ultimately transfer the absorbed energy to chlorophyll a.

Additional Points –

Chlorophyll b: It primarily absorbs blue and orange light and assists chlorophyll a.

Carotenoids: These are yellow, orange, and red pigments that, in addition to absorbing light, protect chlorophyll from damage caused by excessive light.

Anthocyanins: These are water-soluble pigments that impart red, purple, or blue colors to flowers and fruits, but they do not directly participate in photosynthesis.

Potential Exam Questions and Answers –

Question: In which color of light is the rate of photosynthesis highest?

Answer: In red light (followed by blue light).

Question: What causes the yellow color of plant leaves?

Answer: Carotenes and xanthophylls.