Which organelle conducts photosynthesis in plant cells?

• A. Nucleus
• B. Mitochondria
• C. Ribosomes
• D. Chloroplasts

Answer: (D)

Photosynthesis happens in chloroplasts, the green, energy-packed parts of plant cells. These organelles contain chlorophyll, the pigment that captures light energy. When light is absorbed, it drives the light-dependent reactions inside the thylakoid membranes to split water and transfer energy to carriers like ATP and NADPH. Those energy carriers then power the Calvin cycle in the surrounding stroma, where carbon dioxide is fixed into sugars. In short, chloroplasts convert light energy into chemical energy stored as glucose. The nucleus protects genetic material and directs cell activities, mitochondria produce ATP through respiration, and ribosomes synthesize proteins, but the actual process of turning light into chemical energy for the plant is carried out by chloroplasts.