The mitochondria are membrane-bound organelles within cells primarily responsible for producing energy. They generate most of the chemical energy needed to power the cell's biochemical reactions by converting nutrients and oxygen into adenosine triphosphate (ATP), the cell's main energy currency. This process involves pathways such as the citric acid cycle (Krebs cycle) and oxidative phosphorylation

. Besides energy production, mitochondria have several other important functions, including:

• Regulating cellular metabolism
• Signaling through reactive oxygen species
• Calcium signaling and storage
• Mediating cell growth and programmed cell death (apoptosis)
• Participating in steroid and heme synthesis
• Contributing to immune cell function and neuronal signaling
• Generating heat and storing calcium for cell signaling

Mitochondria are dynamic, changing shape and number depending on the cell's energy needs. They contain their own DNA, inherited mostly from the mother, and can reproduce independently within the cell

. Cells with high energy demands, such as muscle, liver, kidney, and brain cells, contain many mitochondria

. In summary, mitochondria are often called the "powerhouses of the cell" because their main role is to produce ATP, fueling cellular activities, while also playing critical roles in metabolism, signaling, and cell survival