By comparing photosynthesis in plants with the respiration (burning our food) that takes place in our own cells, discussed in the last chapter, you can see that, under the skin, animals and plants are not so different. The essential distinction lies in where we, and they, get the fundamental building blocks of life. Both need carbon, but plants obtain it from air whereas we get it from organic sources, such as the plants themselves. Both need electrons to build biomolecules: we burn organic molecules to capture their electrons, while plants use light to burn water to capture its electrons. And
...more
