A bioreactor provides an ideal environment where cells can focus on what they are supposed to do: proliferate. Like lab workers, cells can only produce consistently good work if the conditions are right: it should not be too hot or too cold, and they have to have enough nutritous food and fresh air. In terms of a bioreactor, this means maintaining pH, temperature, ensuring sufficient gas supply and, depending on how the instrument has been configured, adding nutrients for successful maintenance of growth.