Cellular respiration occurs in plant cells as well as animal cells. In this activity, you will measure oxygen consumption by germinating seeds. You need to know that most seeds dry out and are in a dormant condition before germination. In this state, their metabolism is extremely slow. When sufficient moisture is present in the environment, seeds absorb water and swell. This triggers enzyme activity. All seeds store nutrients, usually starch, and the appropriate enzymes digest it to release glucose as an energy source. With a supply of energy, cellular respiration can occur. View the following video to see cress seeds germinating.