 Hey everybody, Dr. O here. In this video we're going to talk about the three types of chemical reactions that are important in human physiology. So we have the synthesis reaction, decomposition reaction, and exchange reaction. So the first one you see there, I love this, I love the way they've done this in the book. A synthesis reaction, you see note plus book creates notebook. Or another way to look at this would be A plus B equals AB. This is any time you take smaller pieces and put them together. These are going to be anabolic reactions, meaning they require energy. It takes energy to build something. Other name for it, and I'll show you on the next slide. Another name for this would be a dehydration or condensation reaction. Because as you build things you often remove water. All right, so those are your synthesis reactions. Then we have the decomposition reaction. When you take something large and break it apart. So here we see bookworm is broken down into book plus worm. Another way to do this would be AB is equal to A plus B. These are going to be catabolic. So as you break large things down, you release energy, digestion, right? The chemical breakdown of all the food we eat into its smallest components that can be absorbed. Great example of catabolic decomposition reactions. These are also often called or they can be hydrolysis reactions. Because oftentimes when you use water to split things apart hydrolysis, hydrolysis. So that's why they're also known as hydrolysis reactions. Then we have the exchange reaction. So the example they give here notebook plus worm equals note plus bookworm. So in this example, it's a combination of a decomposition reaction because you had to break notebook into note and book. And a synthesis reaction because you had to build turn book and worm into bookworm. So it's a paired decomposition and synthesis reaction. So another way you look at this would be A plus BC would be equal to AB plus C. Or you can even have more complicated ones. AB plus CD is equal to AC plus BD, not AC-DC, the band. All right, what else about this? The good example of exchange reaction would be ATP. ATP breaks itself apart, giving away its third phosphate and becoming ADP. And then that phosphate goes and does its job, whatever it is. So you could add a phosphate onto glucose, for example. So that would be an exchange reaction. You broke one thing down to build something else up. All right, so those are the three reaction types. Just a reminder that often water is involved. That's why water is so important to life. It's very, very important in reactivity. So dehydration synthesis reactions because you usually remove water when you build things. And then hydrolysis reactions would be our breakdown decomposition reactions because you often add water when you break things apart. All right, so those are the three major types of chemical reactions in human physiology. I hope this helps. Have a wonderful day. Be blessed.