Hello students. We're going to be talking about chemical reactions here. Chemical reactions are going to be the interactions of our atoms and how they rearrange to form our molecules and compounds. And so, um, we're going to talk about the the symbols and the abbreviations and how we denote these. And when we look at a chemical reaction, we're going to talk about how you how you know what's being put together and what's being taken apart and what direction they're going. And we're going to talk about the energy. Where does it how how do we show where the energy um is being whether energy is being added or taken away or how do you understand that process? And so we'll take a look at that. So when we look at the chemical equation, it has two parts. you have the reactants, the things that are that are coming together that start the the equation and the products which are um going to be the result of the equation. And so they reactants are typically on the left side of the equation and the products are going to be on the right side of the equation. And so they're the the result the end the end game so to speak of of the reaction. Now, some reactions are reversible, and that means they can go the other direction. And in this case, they will typically have an arrow that goes both ways. If they're irreversible, meaning they cannot go both ways, they will just have an arrow going one way, meaning left to right. And so, you'll typically see a single arrow. So, if we look at an example here, we look at this equation, and it's got arrows going both ways. That means both of these reactions go to the right and to the left. So if we look at the reactants, the reactants for this equation right here, so this left part would be CO2, carbon dioxide and water. And the product would be carbonic acid. Okay? And if we were going this way to the left, it would be the opposite. This would be the reactant and this would be the product. So it depends on which direction you're going, but usually you're going left to right. So we'll go this way. And note that this is a reversible reaction because we have two arrows. And in this case, the carbonic acid can also dissociate into bicarbon bicarbonate and hydrogen ions. And so this is a very important equation. I'm just going to tell you this right now. You'll need to know this equation for the rest of the semester. Hint hint. Do you see me winking? This is important. We will talk about this equation every unit and it will probably be on a lot of tests. So just so you know, very very important. We'll talk about it when we talk about buffers and acid base. We're going to talk about it when we talk about um CO2 transport. And um it's it's going to be a big deal. So make sure you you know this equation and again products are the end result. The reactants are the starters. Okay. So energy energy is the capacity to do work. It's going to help you do things. It helps it helps things move. It helps us change things over. We can have what we call potential energy. So, it's energy that's somewhat stored. Okay? So, we can we're holding it for a rainy day. Think of it like putting it in the pantry and you're going to take it out and use it later. Or we can have kinetic energy. Energy that we're using right now. It's the energy that's that's in in use. Basically, that's it. And the more kinetic energy you have, the more movement you have. And so, for um an example of this is molecules that are in the air right now. So the air that is around you, the warmer it is, the more those molecules are moving. And um that's important to understand when we talk about how things react and how fast they react and when we get into our a couple chapters down and we talk about diffusion and the movement across a membrane and how fast it goes, kinetic energy will determine the rates of diffusion. And so that will be important. So the the higher the kinetic energy, the more interactions we will have of molecules because they're moving more. And so when we talk about energy in reactions, there's energy in the bonds. So there's chemical energy, there's energy within the bonds. So if I break these bonds, energy could be released. Or if I I might have to put in energy to form bonds, right? So it it the the energy is used to make bonds and energy is released when we break bonds. And there's electrical energy, energy formed by gradients or the movement of ions or charged particles in certain directions. And so we're going to see this when we talk about electrphysiology, like the movement of sodium ions across a membrane or potassium ions. And that's gonna um that's electrical energy. And the mechanical energy is the energy transferred from one object to another. So like if I push something and it starts to move um that's mechanical energy or if um something you push something and it vibrates, right? Um that is mechanical energy. And so we'll talk about mechanically gated channels and that energy um the vibration energy that causes those channels to move and open. Um it's that energy that that opens those gates. And so that's important. We talk about energy and reactions. When en reactions either require all reactions require some type of energy to get started initially, but overall they may store energy where you have to put more energy in than you actually get out. So there's energy kind of being stored in the in the products. there's more energy um in the products than you actually have in the reactants or that would be endrogonic. So you're you're you're you're kind of storing that energy or exroonic where you're releasing energy. So overall there's more energy in their in the reactants than you have in the product. So energy actually gets released and that is going to allow and that energy that's released can be used to do something. An example of this would be um ATP. ATP has when I when we make ATP it there's a there's more energy in the ATP molecule than there is in the ADP itself. So that would be an endrogonic reaction to to form ATP. It's endergonic because the product ATP has more energy stored in it than the ADP. So we had free energy plus ADP and phosphate. Put that together now we've got stored energy ATP. But then when I break ATP, the pro the products have less energy and that energy gets released and I can use that energy to do something because remember energy on both sides of the equation. Total energy is always going to equal right and left. It doesn't go away. It's still but it's just in a different form. And so if I release that energy, I can use it to do something. types of reactions that I can have catabolic reactions. So, I can break things down. And usually when you're breaking things down, you're releasing energy. Most of these are going to be extroonic reactions. Exchange reactions. These vary. This is where I swap things up. So, I just like, okay, I'm going to take this from you and take this from you and put these together and you two go together. We're going to swap chairs, basically. And then anabolic reactions is where I'm putting things together. So, I'm going to take A and B and put them together and I get AB. And example of that would be I take glucose and a glucose and put them together and I got a moltos, right? Um, and so I'm those are synthesis reactions. I'm putting things and those are typically endrogonic. You're storing energy in those reactions. And here's um some examples of those. So again, if I'm taking these two together, what type of reaction is this? This is going to be an anabolic reaction. I'm putting it together. This is going to I'm this one I'm breaking it apart. So it's a catabolic reaction. And this one I'm swapping. So this is an exchange reaction. Good. So remember catabolic reactions, these are decomposition. These are usually extrogonic and a lot of times these involve the introduction of water to split things apart like hydra hydraysis hydraysis reactions. Um exchange reactions these this is an example of just swapping things out and oxidation reduction reactions. This is a transfer of electrons. So we take electrons we from one thing we give it to another and that transfer of electrons releases energy so we can do something. Okay. So that's an exchange reaction. Another exchange reaction. We're going to talk about this a lot in cellular respiration every day until the cows come home on the in cellular respiration. This is so important. And then anabolic we're putting things together and these are usually dehydration reactions. When we talk about macroolelecule synthesis like um carbohydrates, complex carbohydrates like um starches or glycogen um or proteins or nucleic acids, you you take out um you put in water, sorry, um dehydration is we take out water and we put two things together. And that's that's how we're going to do that. So um that's just what we were talking about dehydration synthesis and hydraysis. So monomers these are the basic building blocks of your macroolelecules and when you put them together you form um chains of these monomers and these will be polymers. Okay? And dehydration synthesis is our way to do that. So we'll take off an O the hydroxal group and an H hydrogen from one end and you put take that out. So you got O and H. That's H2O. Take the take the water out. And now where the O was and the H was, you can now put those together. Okay? And that allows you to put things together. And hydrarolysis, you do the opposite. You put the water in, the O goes on one end, the H goes on the other, and you split things apart. And that's hydroly hydraysis. Or I like to split it up in my mind and say hydrolysis. hydro for water, lis for split. And that way I remember what it's doing. So here's an example of that. You're here you're taking out the water and putting things together. And here you're putting in the water and taking things apart. So our next um chemical level of organization lecture will be on enzymes. We're going to look at how these work. This is going to be really important for your um lab in week two. So, make sure you review this lecture and I will see you there.