The organelle where photosynthesis occurs is the chloroplast. In which cells is this organelle found?

• A. Animal cells
• B. Plant and algae cells
• C. Bacterial cells
• D. Fungal cells

Answer: (B)

Chloroplasts are the sites of photosynthesis, so they appear in cells that perform photosynthesis—mainly plant cells and many algae. These organelles contain chlorophyll, the pigment that captures light energy, and the internal membranes where the light-dependent reactions take place. Through photosynthesis, light energy is used to convert carbon dioxide and water into sugars, fueling the organism. Animal and fungal cells do not photosynthesize and typically lack chloroplasts, which is why their cells don’t contain this organelle. Bacteria can photosynthesize too, but they don’t have chloroplasts as defined organelles inside plant or algal cells.