(N/A) $\Rightarrow$ Mitochondria contain proteins,lipids,enzymes for carbohydrate metabolism,and small amounts of $RNA$ and $DNA$.
$\Rightarrow$ Mitochondria perform three main functions:
$(i)$ Produce cellular energy in the form of $ATP$ and release it as needed.
$(ii)$ Collect,transform,and translocate $ATP$ energy.
$(iii)$ Regulate the active transport of substances across the cell membrane.
$\Rightarrow$ Mitochondria are considered small biochemical factories that generate $ATP$ from food,$ADP$,and oxygen.
$\Rightarrow$ During the chemical process of cellular respiration,glucose molecules are oxidized,yielding $38$ molecules of $ATP$.
$\Rightarrow$ The matrix of the mitochondria contains the necessary enzymes for the Krebs cycle,where $ATP$ is synthesized.
$\Rightarrow$ Therefore,mitochondria are called the powerhouse of the cell.