The mitochondria help cells to get energy from molecules like sugars, proteins, and fats. All living things need water, but they don’t break it down for energy.

The main idea is that big, complicated molecules store energy. When cells break down the molecules, they can use the energy to do work.

The way they do it is a bit complicated, but they use the energy they get from breaking down food molecules to charge up another kind of molecule called ATP. All of the parts of the cell use ATP to do work.

Animals take in these big molecules by eating. Fungi like mushrooms and yeast absorb food. Plants make food themselves by getting energy from the sun and putting water and carbon dioxide together into sugar. This is called photosynthesis. They can send the sugar all over the plant where bigger things can be built from the sugar, or the sugar can be broken down to get the energy out.

Do you think plants have mitochondria?

If you are interested in how cells work, you may want to be a cell biologist.