Which pigment captures light energy for photosynthesis?

• A. Chlorophyll
• B. Carotene
• C. Anthocyanin
• D. Hemoglobin

Answer: (A)

Light capture in photosynthesis relies on pigments that absorb photons and funnel that energy into the photosystems. The primary pigment that does this is chlorophyll, which sits in the thylakoid membranes of chloroplasts and absorbs mainly blue and red light. This absorbed energy excites chlorophyll electrons and begins the electron transport process that powers ATP and NADPH production for sugar synthesis. While carotene and other accessory pigments also absorb light and help transfer energy to chlorophyll (and provide protection against light-induced damage), they don’t act as the main energy-harvesting pigment. Anthocyanin isn’t involved in the photosynthetic light reactions, and hemoglobin is a protein in animals that carries oxygen, not participating in plant photosynthesis.