Which organelle is the site of photosynthesis in plant cells?

• A. Chloroplast
• B. Nucleolus
• C. Vacuole
• D. Endoplasmic Reticulum

Answer: (A)

Photosynthesis uses light energy to convert carbon dioxide and water into glucose, and in plant cells this process happens in chloroplasts. These organelles contain chlorophyll, the green pigment that captures light, and host the machinery for both the light-dependent reactions on their thylakoid membranes and the Calvin cycle in the stroma. The chloroplast’s structure and its own genetic material reflect its specialized role in energy conversion. The other organelles do different jobs: the nucleolus makes ribosomal components inside the nucleus, the vacuole stores water and helps maintain turgor pressure, and the endoplasmic reticulum synthesizes and transports proteins and lipids. So, chloroplasts are the site of photosynthesis.