The Latin verb supponere, meaning substitute, has several legitimate heirs in English, including supposititious (which dates from the early 17th century) and supposition (a 15th century addition).
Cellular respiration takes place in the organelles called mitochondria. The mitochondria take in glucose, a type of sugar, and change it in the presence of oxygen into an energy-rich molecule called ATP, or adenosine triphosphate. For every molecule of glucose, 36 molecules of ATP are made.
Cellular respiration occurs in three main steps. The first step takes place in the cytoplasm of the cell. The last two steps take place in the mitochondria(or if cellular respiration is taking place inside of a plant then the last two steps would take place in the chloroplasts) of the cell.