Which organelle is primarily responsible for photosynthesis?

The chloroplast is the organelle primarily responsible for photosynthesis in plant cells and some other organisms. It contains chlorophyll, the green pigment that captures light energy from the sun. This energy is then used to convert carbon dioxide and water into glucose and oxygen through the photosynthetic process.

Chloroplasts have a complex internal structure that includes thylakoids, where the light-dependent reactions occur, and the stroma, where the light-independent reactions, also known as the Calvin cycle, take place. The entire process of photosynthesis can be summarized as converting light energy into chemical energy, which is stored in glucose, a crucial form of energy for the plant and for organisms that consume plants.

Mitochondria, ribosomes, and the nucleus serve different vital functions; mitochondria are involved in cellular respiration and energy production, ribosomes are the sites of protein synthesis, and the nucleus houses genetic material and controls cellular activities rather than directly participating in photosynthesis.