What organelle in plant cells conducts photosynthesis?

The organelle in plant cells that conducts photosynthesis is the chloroplast. Chloroplasts capture light energy and use it to help convert carbon dioxide and water into energy-rich organic molecules, releasing oxygen during the light reactions.

Inside a chloroplast, the light-dependent reactions occur mainly on membranes called thylakoids. These membranes contain chlorophyll, Photosystem I, Photosystem II, and electron-transport components. Thylakoids are often arranged in stacks called grana. The surrounding fluid, the stroma, contains enzymes used in the Calvin cycle, which incorporates carbon dioxide into carbohydrate precursors.

A common mix-up is choosing mitochondrion. Mitochondria also transform energy, but they carry out cellular respiration rather than photosynthesis. The nucleus stores most of the cell’s genetic information, while the vacuole mainly helps with storage, water balance, and maintaining pressure inside the cell.

Chloroplasts are notable because they contain their own DNA and ribosomes. This supports the endosymbiotic theory that they evolved from ancient cyanobacteria engulfed by an early eukaryotic cell. Chloroplasts are found mainly in plants and algae, and their abundance is especially high in photosynthetic leaf tissues.