Which organelle is primarily responsible for photosynthesis?

Chloroplasts are the organelles primarily responsible for photosynthesis in plant cells and some protists. Within chloroplasts, chlorophyll, the green pigment crucial for capturing light energy, facilitates the conversion of light energy into chemical energy. This process involves the absorption of sunlight, which drives the synthesis of glucose from carbon dioxide and water, releasing oxygen as a byproduct. Chloroplasts contain the necessary machinery, including thylakoids where the light-dependent reactions occur and the stroma where the Calvin cycle takes place.

In contrast, mitochondria are involved in cellular respiration, where they produce energy in the form of ATP by breaking down glucose. The nucleus serves as the control center of the cell, housing genetic material and coordinating various cellular activities, while ribosomes are the sites of protein synthesis, translating genetic information into functional proteins. Understanding the specific roles of these organelles highlights why chloroplasts are uniquely suited for photosynthesis.