Autotrophs, such as plants, make their own food through a process called photosynthesis. Photosynthesis takes place in the chloroplasts. Plants use energy from the sun, water, and carbon dioxide (CO₂) to make glucose (C₆H₁₂O₆). The glucose provides food for the plants and other organisms that eat the plants, and the food is transformed into usable energy.

The chemical equation is as follows:

All living things need energy. Cellular respiration is the process that makes this happen! Cellular respiration occurs in the mitochondria. Organisms consistently need energy, so this cycle is continuous. Unlike photosynthesis, respiration can happen with or without light. The whole purpose of cellular respiration is to release the energy from food and package that energy into an energy molecule (ATP).

The chemical equation is as follows: