Anabolism and Catabolism: Definitions & Examples

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  • 0:06 Metabolism in Your Body
  • 1:39 Catabolism Breaks Down…
  • 2:42 Anabolism Builds Molecules
  • 3:55 Lesson Summary
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Lesson Transcript
Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

Metabolism breaks down large molecules like food into usable energy. This energy drives bodily processes critical to survival. In this video lesson, you will learn about the two forms of metabolism that break down and build up molecules and see examples of each.

Metabolism in Your Body

Have you ever wondered what happens to the food that you eat after it enters your body? As you probably know, food not only tastes good, but it also provides nutrition for all of the different components of your body - bones, muscles, brain function, and much more!

A salad is chock full of nutritious goodies, but your body can't do much with the food as it is. So as food enters your body, it gets broken down into molecular components so that you can actually use the nutrition these molecules provide. All of the physical and chemical activities in your body that convert or use energy are called metabolism. These include things like breathing, digesting food, and circulating blood.

But metabolism is a pretty broad term, and it includes all of the chemical activities in your body. We can think of metabolism in two separate forms: catabolism and anabolism. Catabolism involves all of the metabolic processes that tear down biomolecules, while anabolism is all of the metabolic processes that build biomolecules.

One way to remember which is which is to think of 'catastrophe' for catabolism and 'steroids' for anabolism. During a catastrophe like an earthquake, large buildings and other structures fall apart, just like molecules get broken apart during catabolic reactions. People use anabolic steroids to build up their muscles, just like anabolic reactions 'build' biomolecules.

Catabolism Breaks Down Molecules

Catabolic reactions are reactions that involve the breakdown of biomolecules, but what exactly does this mean? When you eat food, you chew it to make it easier to swallow, right? Catabolic reactions are similar in that they 'chew' up biomolecules to make them easier to utilize.

Digestion is a catabolic activity. Here, you begin with large food molecules, and then water is used to break the bonds in those molecules. These smaller molecules are then sent off to the cells in your body to participate in cellular respiration, which is a process that converts biochemical energy to ATP, a very high-energy molecule.

Cellular respiration is also a catabolic process because it breaks the small molecules from digestion into even smaller ones as ATP is created. These are both very important processes, because ATP is what your cells use to produce body heat, move your muscles, and other essential bodily functions.

Anabolism Builds Molecules

ATP not only provides energy to your cells, it also allows anabolic processes to occur. Anabolism is the reverse of catabolism, since these reactions build large biomolecules from smaller ones. And the molecules that are produced are the same types as what you find in food, such as carbohydrates and proteins. In a sense, these molecules are like your body's own version of the food it originally came from.

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