 Photosynthesis makes usable energy for us. It makes energy that we can eat. We can't eat light, although I'll tell you right now, if I could, I would be the happiest camper on the planet. Photosynthesis, using the energy from light, this is the chemical equation for photosynthesis. It takes carbon dioxide out of the air and a little bit of water and sunshine. It uses energy from the sun and uses all of that stuff, the energy from the sun, the water and the carbon dioxide, to build glucose, C6H12O6, and water. No. Something else. Really? Oxygen. Of course, I knew there was something else there. Oxygen is one of the byproducts of photosynthesis, which is why we say, dude, don't chop down all the trees because they're actually taking carbon dioxide out of the air and making glucose, which we can use, and breathing out or emitting oxygen as a byproduct. Once you come along, I'll draw a picture of you next. Look at your little cute self. Oh, I'm having a hard time picking a color here. It's you. And you're going to eat that apple. And how do you get the energy out of the apple? Well, we know that the apple created glucose. So let's go ahead and write down the process, which is cellular respiration, cellular respiration. Cellular respiration is taking that glucose molecule seriously. B6H1206, adding in some oxygen that you just breathed in, producing carbon dioxide, and, take a wild guess, water, and what? Energy. And are we emitting sunlight energy? So, in fact, we take this process, makes a new molecule, ATP, which is basically like energy money inside a living system. ATP can be used to power almost everything, including the sodium-potassium pump. Remember that guy that was doing primary active transport? Pumping sodium and potassium ions against the concentration gradient? ATP was required to do that, which means that you had D to gummy bear, or some form of carbohydrate, to get the glucose. You had to breathe to get the oxygen. And then the mitochondria, oh, glory days, went through the process of cellular respiration and delivered a fat chunk of ATP for you to use in powering your sodium-potassium pump in contracting your skeletal muscles, in dealing with smooth muscle contraction, keeping your heart beating, letting your brain work on and on and on, all the things that you need energy for, like jumping over your wife at your wedding. Hopefully, you have a good sense of energy. And we're going to play with it. We're going to blow up some gummy bears. We're going to play with some magnets. We're going to do some challenges in class to hopefully get this concept solidified. The next two lectures are dealing just with cellular respiration and just with photosynthesis.