Knock out the power supply
A knock-out test with a control
Teaching this? Open projector mode
One way to find out what a part does is to remove it and see what fails: a knock-out experiment. Biologists do it with drugs and gene changes, and nature does it too: mature human red blood cells have no mitochondria and no nucleus. A fair test needs a control, the same cell under the same conditions with nothing removed. Mitochondria run aerobic respiration and make about 30 ATP from each glucose; without them, glycolysis in the cytoplasm still makes 2. Many other jobs, such as building proteins, making lipids and digesting waste, use ATP. So removing one part can have a direct effect and knock-on effects. Predict first, then run.
A plant cell is kept in the dark and all its chloroplasts are knocked out. What does the one-minute test show?