Which structure is responsible for photosynthesis?

The structure responsible for photosynthesis is the chloroplast. Chloroplasts are specialized organelles found in plant cells and some protists that capture light energy from the sun and convert it into chemical energy through the process of photosynthesis. This process involves the transformation of carbon dioxide and water into glucose and oxygen, using sunlight as the energy source. Chloroplasts contain chlorophyll, the green pigment that absorbs light, primarily in the blue and red wavelengths, which is crucial for capturing the solar energy needed for photosynthesis.

The other structures mentioned play different roles within the cell: mitochondria are involved in cellular respiration, ribosomes are essential for protein synthesis, and the nucleus contains the genetic material and regulates cell activities. However, none of these other organelles are directly involved in the conversion of light energy into chemical energy, which is the primary function of chloroplasts.