Overview of metabolism Anabolism and catabolism Biomolecules MCAT Khan Academy
Textbooks define metabolism, a topic in biochemistry, as a series of chemical reactions that take place inside of our bodies to sustain life. Now, this is a pretty broad definition of metabolism. So in this tutorial, I really want to break this definition down to a more workable understanding of what metabolism really is.
So first, I’m going to introduce another arrow in this diagram, like this, and say that really, the requirements of life, let’s say in a human being, such as maintaining a constant internal temperature, reproducing, growing, and all that jazz, all of that ultimately boils down to the body’s ability to utilize four essential biomolecules. And these four essential biomolecules, or as they’re sometimes known as macromolecules,.
Are proteins, fats, carbohydrates, or carbs, and nucleic acids, like DNA and RNA. And ultimately, all of these biomolecules perform different lifesustaining reactions inside of all of the cells in our body to ultimately promote life. So as you can see, we’ve already begun to break down this definition of metabolism.
Essentially what we’re saying here is that metabolism is really the study of how we’re able to obtain these important biomolecules to sustain life. So how do we obtain these biomolecules? Now, a simple answer to this question is, of course, that we eat food to obtain all of these important biomolecules. But there is an important word of caution.
Here, which is that since most food comes from living organisms like plants and animals, these plants and animals also contain an array of proteins, fats, carbohydrates, nucleic acids, but not necessarily in the same flavor or configuration that our bodies would prefer. So what do our bodies do instead? Well, in our bodies, we go ahead and eat the food.
That’s a very large head there, but you get the idea. And in our bodies, we break down this food through a process called digestion into the component parts of all of these biomolecules. So what do I mean by component parts? Well, the smallest subunit of proteins is called an amino acid. And our body breaks down all the different types.
Of proteins that we digest into individual amino acids. And the same pattern continues for the rest of the biomolecules. So in the case of fats, we’re talking about fatty acids, which are the smallest subunits of fats. And then for carbohydrates, which are long chains of sugars. One of the most common subunits of carbohydrates.
ATP Respiration Crash Course Biology 7
Oh, hello there. I’m at the gym. I don’t know why you’re here, but I’m going to do some pushups, so you can join me on the floor if you want. Now, I’m not doing this to show off or anything. I’m actually doing this for science. pained grunt You see what happened there? My arms moved, my shoulders moved, my back and stomach muscles moved, my heart pumped blood to all those different places. Pretty neat, huh? Well, it turns out that how we make and use energy is a lot like sports or other kinds of exercise.
It can be hard work and a little bit complicated but if you do it right, it can come with some tremendous payoffs. But unlike hitting a ball with a stick, it’s so marvelously complicated and awesome that we’re still unraveling the mysteries of how it all works. And it all starts with a marvelous molecule that is one of you best friends: ATP. Today I’m talking about energy and the process our cells, and other animal cells, go through to provide themselves with power. Cellular respiration is how we derive energy from the food we eatspecifically from glucose,.
Since most of what we eat ends up as glucose. Here’s the chemical formula for one molecule of glucose C6H12O6. In order to turn this glucose into energy, we’re going to need to add some oxygen. Six molecules of it, to be exact. Through cellular respiration, we’re going to turn that glucose and oxygen into 6 molecules of CO2, 6 molecules of water and some energy that we can use for doing all our push ups. So that’s all well and good, but here’s the thing: We can’t just use that energy to run a marathon or something. First our bodies have to turn that energy into a really specific form of stored energy called ATP, or adenosine triphosphate. You’ve heard.
Me talk about this before. People often refer to ATP as the quot;currencyquot; of biological energy. Think of it as an American dollarit’s what you need to do business in the U.S. You can’t just walk into Best Buy with a handful of Chinese yen or Indian rupees and expect to be able to buy anything with them, even though they are technically money. Same goes with energy: In order to be able to use it, our cells need energy to be transferred into adenosine triphosphate to be able to grow, move, create electrical impulses in our nerves and brains. Everything. A while back, for instance, we talked about how cells use ATP to transport some kinds of materials in and out of its membranes; to jog your memory about.
That you can watch it right here. Now before we see how ATP is put together, let’s look at how cells cash in on the energy that’s stashed in there. Well, adenosine triphosphate is made up of an nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it: Now one thing you need to know about these 3 phosphate groups is that they are super uncomfortable sitting together in a row like that like 3 kids on the bus who hate each other all sharing the same seat.
So, because the phosphate groups are such terrible company for each other, ATP is able to do this this nifty trick where it shoots one of the phosphates groups off the end of the seat, creating ADP, or adenosine diphosphate (because now there are just two kids sitting on the bus seat). In this reaction, when the third jerk kid is kicked off the seat, energy is released. And since there are a lot of water molecules just floating around nearby, an OH pairing that’s called a hydroxide from some H2O comes over and takes the place of that third phosphate group. And everybody is much happier. By the way? When you use water to break down a compound like this, it’s called hydrolysis.
hydro for water and lysis, from the Greek word for quot;separate.quot; So now that you know how ATP is spent, let’s see how it’s minted nice and new by cellular respiration. Like I said, it all starts with oxygen and glucose. In fact, textbooks make a point of saying that through cellular respiration, one molecule of glucose can yield a bit of heat and 38 molecules of ATP. Now, it’s worth noting that this number is kind of a best case scenario. Usually it’s more like 2930 ATPs, but whatever people are still studying this stuff, so let’s stick with that 38 number.