Which organelle is the site of photosynthesis?

Which organelle is the site of photosynthesis?

• A. Nucleus
• B. Chloroplast
• C. Mitochondrion
• D. Ribosome

Answer: (B)

Photosynthesis happens in chloroplasts in plant cells and many algae. Chloroplasts contain chlorophyll, the pigment that captures light energy. In the thylakoid membranes, the light-dependent reactions use that energy to split water and generate ATP and NADPH. In the surrounding stroma, the Calvin cycle uses those energy carriers to fix CO2 into sugars. That combination of light capture and the biochemical machinery for building sugars is why chloroplasts are the site of photosynthesis. The nucleus stores genetic material, mitochondria carry out cellular respiration, and ribosomes are the sites of protein synthesis, so they don’t perform photosynthesis.

Photosynthesis happens in chloroplasts in plant cells and many algae. Chloroplasts contain chlorophyll, the pigment that captures light energy. In the thylakoid membranes, the light-dependent reactions use that energy to split water and generate ATP and NADPH. In the surrounding stroma, the Calvin cycle uses those energy carriers to fix CO2 into sugars. That combination of light capture and the biochemical machinery for building sugars is why chloroplasts are the site of photosynthesis. The nucleus stores genetic material, mitochondria carry out cellular respiration, and ribosomes are the sites of protein synthesis, so they don’t perform photosynthesis.