Chapter 7: How cells harvest energy

Energy drives everything of life. Energy is required for every action a creature takes, including the purring of a cat, the swimming of bacteria, and even the thoughts you are having as you read this. This chapter covers the mechanisms that every cell employs to obtain chemical energy from organic molecules and transform that energy into ATP. After that, in chapter 8, we'll look at photosynthesis, a process that converts light energy into chemical energy. Because all animals, including the photosynthesizing plant and the caterpillar eating the plant in the picture, are able to obtain energy through chemical bonds, we first take into account the conversion of chemical energy to ATP. Respiration is a universal technique for obtaining energy.