What is the powerhouse of the cell?

The mitochondria are known as the powerhouse of the cell because they are responsible for producing adenosine triphosphate (ATP), which serves as a primary energy carrier in cells. Through the process of cellular respiration, mitochondria convert nutrients such as glucose into ATP, releasing energy that the cell can utilize for various metabolic activities. This energy production is vital for sustaining the life functions of the cell.

The other options, while important cellular components, serve different functions. The nucleus is primarily involved in storing genetic material and regulating cellular activities. Chloroplasts are found in plant cells and play a critical role in photosynthesis, converting light energy into chemical energy. Ribosomes are the sites of protein synthesis, translating messenger RNA into polypeptides but do not generate energy like mitochondria. Thus, the unique role of mitochondria in ATP production firmly establishes them as the powerhouse of the cell.