We can measure the uptake of oxygen in a given time to work out the rate of respiration.

Animals, plants and many other living organisms inhale oxygen to "burn" (oxidize) compounds like sugar into CO 2 and water—a process during which the energy-rich molecule ATP is produced.

Cellular nutrients come in many forms, including sugars and fats. In order to provide a cell with energy, these molecules have to pass across the cell membrane, which functions as a barrier ...