The most common and abundant pigment is chlorophyll a . Only certain organisms, called autotrophs, can perform photosynthesis; they require the presence of chlorophyll, a specialized pigment that can absorb light and convert light energy into chemical energy.

Eukaryotic autotrophs, such as plants and algae, have organelles called chloroplasts in which photosynthesis takes place In the first part of photosynthesis, the light-dependent reaction, pigment molecules absorb energy from sunlight.

light-dependent reaction — the first stage of photosynthesis where visible light is absorbed to form two energy-carrying molecules (ATP and NADPH). pigment — a molecule that is capable of absorbing light energy. chlorophyll — the green pigment that captures the light energy that drives the reactions of photosynthesis. chlorophyll a — the form of chlorophyll that absorbs violet-blue and red light.