Which organelle is known as the powerhouse of the cell?

The mitochondria are known as the powerhouse of the cell because they are the primary site of adenosine triphosphate (ATP) production through cellular respiration. ATP is often referred to as the energy currency of the cell, as it provides the necessary energy for various biochemical processes that are essential for cell survival and function. Mitochondria convert nutrients, particularly glucose and fatty acids, into energy in the form of ATP by using oxygen in a process called oxidative phosphorylation.

In addition to ATP production, mitochondria are also involved in a variety of other critical cellular processes, including the regulation of metabolic pathways, the activation of certain signaling pathways, and the regulation of apoptosis (programmed cell death). Their unique double membrane structure and their own DNA further highlight their essential roles in energy metabolism.

Other organelles mentioned, like ribosomes, are primarily involved in protein synthesis; the nucleus is the control center of the cell containing genetic material; and lysosomes are responsible for breaking down waste materials and cellular debris. While each of these organelles has its own vital function, none can match the mitochondria's designation as the powerhouse due to their pivotal role in energy production.