Two-membrane cell organelles storing ATP energy.

In a eukaryotic cell, two plastid organelles are two membranous – the structure of the plant cell and mitochondria – are present in both plant and animal cells. Thylakoids are the inner membrane of the plastids, in mitochondria – the cristae.

In plastids and in mitochondria, the ATP molecule can be synthesized – the main source of energy. But the largest number of ATP molecules can be stored in mitochondria. Only decomposition reactions of organic substances proceed on cristae, and the released energy is spent on the synthesis of ATP.