What function do mitochondria serve in a cell?

Mitochondria are often referred to as the "powerhouses" of the cell because their primary function is to facilitate cellular respiration, which is the process that converts biochemical energy from nutrients into adenosine triphosphate (ATP). ATP is the energy currency of the cell, enabling various cellular processes that require energy.

In mitochondria, the process of aerobic respiration occurs, which includes stages such as the Krebs cycle and oxidative phosphorylation. During these processes, glucose and other fuels are broken down, and in the presence of oxygen, energy is captured in the form of ATP. This is crucial for sustaining cellular functions and overall energy metabolism.

Other options pertain to distinct cellular functions not associated with mitochondria. For instance, protein synthesis generally occurs in ribosomes, while genetic material is stored within the nucleus of eukaryotic cells. Lipid synthesis is primarily conducted in the smooth endoplasmic reticulum. Thus, option B accurately reflects the vital role that mitochondria play in energy production and metabolism within the cell.