In this video, we're going to begin our introduction to metabolism. Metabolism is a term that refers to all of an organism's chemical reactions. When we talk about all the chemical reactions inside an organism, that is what metabolism refers to. Now, metabolic pathways are defined as a series of chemical reactions that ends up altering a substrate multiple times before the final product is released. Notice the example image below, showing an image of a metabolic pathway. Metabolic pathways have multiple steps. Notice that the very first substrate here, substrate A, is being converted into product B by enzyme number 1, but notice that product B is not the final product. Instead, B is going to be converted into C by enzyme 2, and C is further going to be converted into D by enzyme 3. Last but not least, D is going to be converted into E by enzyme 4. In this example, molecule E is acting as the final product to this pathway, and all these others, molecules that we see here are acting as substrates to enzymes. What we can see here is that enzymes work together in a series of steps to convert one substrate into another until the final product is released. When enzymes work together in this fashion, we refer to it specifically as a metabolic pathway. There are two main types of metabolic pathways that you should be aware of, and we'll introduce those two in our next video. I'll see you all there.
Introduction to Metabolism - Online Tutor, Practice Problems & Exam Prep
Metabolism encompasses all chemical reactions within an organism, organized into metabolic pathways that convert substrates into products through a series of enzymatic steps. These pathways are categorized into catabolic pathways, which release energy by breaking down larger molecules, and anabolic pathways, which require energy to synthesize larger molecules from smaller ones. Catabolism is associated with exergonic processes, while anabolism involves endergonic processes. Understanding these pathways is crucial for grasping how organisms manage energy and build essential biomolecules like proteins and DNA.
Introduction to Metabolism
Video transcript
Catabolic & Anabolic Pathways
Video transcript
In this video, we're going to distinguish between Catabolic and Anabolic Pathways. There are 2 main types of metabolic pathways. The first type is catabolic pathways or catabolism, and the second type is anabolic pathways or anabolism. Catabolic pathways, or catabolism, release energy into the environment by breaking down molecules into smaller ones. Anabolic pathways, on the other hand, spend energy or require an energy input to build up larger molecules such as DNA and proteins. As such, catabolic pathways are associated with exergonic processes due to their energy-releasing nature, while anabolic pathways are associated with endergonic processes due to their energy-consuming nature.
Let's take a look at our image below to further distinguish between catabolic and anabolic reactions and pathways. Notice on the left-hand side we're focusing on catabolism, where molecules break down from large molecules into their smaller components. On the right-hand side, we focus on Anabolism, which involves the building of larger molecules using smaller ones. When you think about catabolism, consider the word "cat" embedded within it; catabolism involves breaking things down, analogous to a cat pouncing on a pyramid and breaking it into smaller components. However, a cat cannot build a pyramid, which illustrates the one-way nature of catabolism.
On the other hand, anabolism, lacking the word cat, suggests the absence of breaking down, thus allowing for building up. Here, for metabolism, the cat breaks down the molecules into its smaller components, while an enzyme is shown breaking down a larger molecule. For anabolism, we are showing how building blocks are built up into a larger, more structured pyramid, and smaller building blocks are converted into larger pieces by an enzyme, illustrating the build-up process. This is the main difference between catabolism and anabolism: catabolism breaks down, whereas anabolism builds up.
That concludes our introduction to catabolic and anabolic pathways, and we will get some practice applying these concepts as we move forward in our course. I'll see you all in our next video.
Which of the following terms specifically describes the metabolic process of breaking down large molecules?
Catabolism.
Metabolism.
Anabolism.
Dehydration.
Which of the following statements is TRUE regarding anabolic pathways?
They are used for digesting sugars.
They consume energy to build up polymers from monomers.
They release energy by breaking down polymers into monomers.
They increase the entropy of the organism.
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