In this video we're going to look at the different types of respiration and why the reaction is so important. If we think about the energy that we use to function, the majority of it comes from molecules of glucose, which were originally made by plants during photosynthesis. To release this energy we use a process called cellular respiration, which we can describe as an exothermic reaction which transfers energy from glucose and is continuously occurring in living cells.
So basically it involves breaking apart glucose molecules to release the energy that's trapped inside. Notice that I keep saying release energy, that's because energy isn't being made, it's just being transferred from the glucose molecules. And all exothermic means is that the reaction releases energy. Before we explore how respiration works, Let's take a look at three examples of how organisms use their energy.
One is to build up larger molecules from lots of smaller ones, for example combining amino acids to form proteins. Another is for muscular contraction, so that we can move about. And the third is maintaining our body temperature, so that we stay nice and warm, even in colder environments. As we said a minute ago, these are only a few examples. Energy is actually needed for loads of reactions in our cells all the time, most of which are catalysed by enzymes.
As an aside, we call the combination of all of these reactions, and also lots that don't require any energy, as metabolism, which we can define as all the chemical processes that occur within a living organism in order to maintain life. Getting back to respiration though, there are two types that you need to know about. Aerobic respiration and anaerobic respiration. Aerobic respiration is the more common type, and takes place whenever there's enough oxygen, which is the key point to remember.
It's by far the most efficient way to transfer energy from glucose, and it takes place continuously in both plants and animals. Specifically though, it takes place within the subcellular structures known as mitochondria. The word equation for aerobic respiration is glucose plus oxygen, goes to form carbon dioxide plus water.
It's also important to note the chemical symbols though, and notice that there's six of everything except glucose, because glucose is a much larger molecule. If you remember the equation for photosynthesis, you might notice that this equation is the exact opposite, because photosynthesis produces the glucose in the first place. Now, anaerobic respiration is basically respiration without oxygen.
We only do this when we really have to. For example, when we're sprinting and can't get enough oxygen to our tissues in order to keep up with the demands of the more efficient aerobic respiration. The word equation for anaerobic respiration is glucose goes to form lactic acid, and there are really two reasons why we prefer not to use it.
One, is that there's incomplete breakdown of the glucose molecule because there's no oxygen to oxidise it, which makes the whole process inefficient because we're not unlocking all of the energy within the glucose molecule. The second problem is that lactic acid builds up, which has to be removed later, as we'll see in our next video on exercise. The last thing we need to cover is anaerobic respiration, implants and yeast, which is a bit different.
This time, the glucose is converted to ethanol and carbon dioxide instead of lactic acid. In the case of yeast, we call this process fermentation, and we take advantage of it in industry. For example, we add yeast to bread so that the carbon dioxide it produces forms little pockets of air that make the bread appear light and fluffy. And because fermentation produces ethanol, which is a type of alcohol, we also use yeast to make beer and wine.
And that's everything for this video. Cheers for watching and we'll see you next time.