 Metabolism is complicated. I feel like I need to start with the terminology video so we're speaking the same language. That way when I'm talking about something like anabolism or these types of things in the future you'll have a solid foundation of what the word means so you can focus on what's actually occurring during the Krebs cycle or wherever we're at. So your metabolism right when you think metabolism you probably think how many calories that I burn on the treadmill today how many donuts can I eat without gaining weight. That is one way to look at metabolism but the true definition of your metabolism would be the sum of all the energy consuming and energy releasing processes in your body. So if you have a higher metabolism because you are an athlete and you're training really hard it's because there are going to be a lot more of those processes. You're going to be spending a lot more energy because you're going to be building muscle and repairing tissues etc. So the two are related but the actual biochemical definition of metabolism one more time is the sum of all the chemical processes or all the energy consuming and energy releasing processes in your body. So that's metabolism. How I like to define it though in the classroom is metabolism is equal to anabolism plus catabolism. So those are two more very important words you can see them here on the screen. Anabolism or anything that's anabolic is going to require energy to build something. How I remember that anabolic steroids make you bigger not small smaller. So anabolism is the building up of things that requires energy. It takes energy to build something. Catabolism or something is catabolic. It's going to break something down and release it. So the best examples here think about like digestion. So when you take in your food it's large and complex when you digest it you're breaking it down into smaller and smaller processes. So digestion is very catabolic and then once you've digested your food you get into the bloodstream and then you're going to further break it down in your metabolic pathways that we're going to cover in this unit. And as you're tearing apart the glucose from your pancakes or whatever it's going to be breaking that into smaller and smaller pieces and releasing energy. So digestion and cellular respiration your metabolic pathway primary metabolic pathway are both very catabolic. So they're going to break things apart and release energy. Well the cool thing about that is we get our energy and our chemical building blocks from the same place. So when you're digesting and breaking apart your food not only are you releasing energy but you're creating the building blocks that we need. So then we switch to anabolism. We take the energy we extracted from our breakfast. We take the building blocks. We digested from our breakfast and we put them together. And we take the energy and take the building blocks and we build you. This whole idea is you are what you eat, right? So the protein you ate in your meals becomes the protein in your muscles. So the protein in your hormones, et cetera, et cetera. So that's why your entire metabolism can be broken down into those two halves. What are the anabolic things that require energy and lead to growth? What are the catabolic things that break things apart and release energy? All right, other terms you're going to hear a lot in this unit are going to be oxidation and reduction. So this is the transfer of electrons. And the key thing to remember is when you transfer an electron you transfer a little bit of energy with it. So this transfer of electrons all throughout your metabolism is what leads to the steady accumulation of energy. That energy is going to be used to turn ADP, adenosine diphosphate, into ATP, adenosine triphosphate, which will do a whole start video on ATP. That's the cellular energy currency that your body uses. So oxidation is when you release an electron. And then with that release of an electron, a little bit of energy is released or transferred as well. Reduction is going to be when that electron is added somewhere else. So how I remember it, it's kind of silly. But when you reduce something, you make it bigger. I remember it because it doesn't make sense. So oxidation peels an electron off of something. Think about like metal rusting or that you're apple oxidizing and kind of breaking down. So oxidation peels electrons off. Reduction is where that electron ends up. It's going to be added somewhere else. And oxidation is important in lots of places. We care about it right here with your metabolism. But we use oxidation to kill microbes and microbiology and all manner of things. All right, so that is oxidation and reduction. So far we've covered metabolism, anabolism, catabolism, oxidation reduction, and I did mention ATP, adenosine triphosphate. So we're talking about transferring electrons in these oxidation and reduction reactions. Where do they go? Well, your two electron carriers, your electron transporters, which are wildly important in this unit, are NAD and FADH. And as they pick up electrons and pick up hydrogen ions, they become NADH and FADH2. I never asked you to know their actual names, but NAD is nicotinamide, adenine, excuse me, dinucleotide. But the key thing to note there is nicotinamide should make you think of niacin. So it's built from the B vitamin niacin. And then FAD is flavin, adenine, dinucleotide. So flavin think riboflavin. So they are made from the B vitamins niacin and riboflavin. The other key things to note here are that NAD, as it transfers electrons to your electron transport system, NADH is worth three ATPs, and FADH2 is going to be worth two. All right, a few more terms here. We have dehydration versus hydrolysis. So as you can see on the top, when you take two small building blocks and put them together, you remove a water. So that's why, so when you synthesize things, they undergo what's called a dehydration reaction. Because as you can see there, water is removed as two smaller pieces are put together. The opposite occurs when you break things down. So breaking things down is going to be undergo hydrolysis reactions, where you add water and that splits your large compound down into two smaller ones. So that those are dehydration and hydrolysis reactions. All right, last screen here. As far as ways to classify organisms using terminology, first we have the old producers and consumers, right? Producers get their energy from the sun. They can make their own energy. Consumers, if you think about it, we have to consume our energy. We can't get it from the sun. But all energy does come from the sun. So if you think about it, you and me, we're consumers. The bacteria we care about are consumers, et cetera, et cetera. But what are we? We are really packets of stored sunlight energy. Because all the energy in my body right now came from a plant that got its energy from the sun. Or it came from an animal that got its energy from a plant that got it from the sun. So that's one interesting way to look at you. As a consumer, you're consuming sunlight energy. You're just consuming it after some intermediate has stepped between you and the sunlight energy and turned it into the chemical energy that you can use. So those are producers versus consumers. The other terms you're going to see here on the screen, we have autotrophs and heterotrophs. So autotrophs are going, that means self-feeders. That means they can create their own energy. Heterotrophs are other feeders, which means they have to get their energy from other things. So a plant would be a really good example. As you can see here, a photo autotroph because they get their energy from light. So that's where the photo comes from and they can feed themselves as they take light energy. They take carbon dioxide and they take water. They can build their own food, which they then go and eat. So they're autotrophs. We're heterotrophs. We have to get our energy from other living things. We have to get our energy from other carbon sources. So it makes us cool though. So I do want you to know this, by far the most important one because all animals like us and then almost all the bacteria we care about in microbiology are going to be chemoheterotrophs, which means we get our energy from chemical sources, chemical energy, but we can't make it ourselves. That's what makes us heterotrophs. So when we eat something, the cool thing is that we get our chemical energy, the energy and the building blocks that we need from the same food. So we get our carbon sources and our source of electrons from the same place. And that's really nice. Right? Imagine if you had to eat one kind of food for energy and one kind of food for building blocks. Thankfully that doesn't happen. And that's because all living things are connected by the same DNA. Okay. I know that's a lot, but I want the terminology to sink in so as we're diving deeper, at least you have a little bit of a background here. So I hope this helps. Have a wonderful day. Be blessed.