Oxysomes occurs in

Oxysomes occur in Mitochondria.
Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy.
Oxysomes are small round bodies found in the folds of the cristae in the inner mitochondrial membrane and are involved in ATP synthesis. The folds are studded with small round bodies known as F₁ particles or oxysomes.