In this video, we're going to begin our introduction to aerobic cellular respiration. Aerobic cellular respiration, as its name implies, is the aerobic process of breaking down the sugar glucose, which acts as food for the cell, in order to make lots of energy for the cell in the form of ATP. Now, "aerobic" is a term that refers to the requirement of the presence of oxygen gas, and the chemical formula for oxygen gas is O2. Moving forward in our course, we're mainly going to focus on aerobic cellular respiration, or cellular respiration in the presence of oxygen gas. However, in some of our videos much later in our course, we'll also discuss what happens with cellular respiration under anaerobic conditions when there is no oxygen present. But for now, we're going to focus on aerobic cellular respiration. Aerobic cellular respiration actually occurs in multiple different stages that we'll discuss more as we move forward in our course. Most of these stages of aerobic cellular respiration occur inside the organelle called the mitochondria in eukaryotic cells. Recall that only eukaryotic cells contain mitochondria, and prokaryotic cells do not contain those membrane-bound organelles like mitochondria. Most of the stages of cellular respiration occur in mitochondria in eukaryotes. But there is one stage, specifically glycolysis, that we'll discuss more later in our course, that occurs just outside the mitochondria. Other than that, all the other stages occur in the mitochondria in eukaryotes. Now, in prokaryotes, on the other hand, they again lack mitochondria. They are still able to perform aerobic cellular respiration; it's just that the location of the stages of aerobic cellular respiration is going to be different. Because prokaryotes lack mitochondria, most of the cellular respiration stages are going to occur in the cytoplasm of the prokaryotic cells. We'll talk more about these stages of aerobic cellular respiration as we move forward in our course. As we progress, we're mainly going to focus on aerobic cellular respiration in eukaryotes. You'll frequently see us showing the mitochondria. Whenever you see the mitochondria, you can assume that this process is occurring in eukaryotic organisms. We'll discuss a little about cellular respiration in prokaryotes and will specifically mention the most important features that you should know about cellular respiration in prokaryotes as we move forward. But for now, let's take a look at this image down below here, which is showing you the overall chemical equation for aerobic cellular respiration, an important equation for you to be familiar with. Notice that we're showing you aerobic cellular respiration occurring mainly inside the mitochondria in eukaryotic organisms. The chemical equation for aerobic cellular respiration begins with glucose and oxygen gas as reactants. These reactants undergo many different stages of cellular respiration, represented by a single arrow, and, ultimately, glucose and oxygen gas are converted into carbon dioxide, water, and ATP, a form of energy for the cell. The main purpose of cellular respiration is for the cell to obtain this energy because it can use this ATP to drive many other cellular processes. This is just our introduction to aerobic cellular respiration, and we'll be able to talk a lot more about this process as we move forward in our course. I'll see you all in our next video.