Question

How mitochondria produce energy or ATP?

Answer 1

Mitochondria: the energy converters
Mitochondria, using oxygen available within the cell convert chemical energy from food in the cell to energy in a form usable to the host cell. The process is called oxidative phosphorylation and it happens inside mitochondria. In the matrix of mitochondria the reactions known as the citric acid or Krebs cycle produce a chemical called NADH. NADH is then used by enzymes embedded in the mitochondrial inner membrane to generate adenosine triphosphate (ATP). In ATP the energy is stored in the form of chemical bonds. These bonds can be opened and the energy redeemed.

In return the host cell provides physical protection and a constant supply of food and oxygen.