7.1 Integration of Macronutrient and Alcohol Metabolic Pathways

Integration of Macronutrient and Alcohol Metabolic Pathways

If you were to draw all the macronutrient and alcohol metabolic pathways covered in chapter 6, hopefully it would look something like the figure below. Again, don’t be overwhelmed by its complexity. If you take some time to look through it, you will see many things we discussed in Chapter 6, including how acetyl-CoA is right in the center of it all. Also remember that the Krebs Cycle is another term for the Citric Acid Cycle.

In this figure:

Carbohydrate pathways are orange Triglyceride/fatty acid pathways are purple Protein/amino acid pathways are green Non-classified pathways are gray

Figure 7.11 Integrated macronutrient and alcohol metabolism1

To simplify, we are going to remove the glycerol and cholesterol pathways so that we can focus on integrating the other pathways in macronutrient and alcohol metabolism.

Figure 7.12 Removal of glycerol and cholesterol pathways1

Thus, we are left with the following simplified figure:

Figure 7.13 Simplified integrated macronutrient and alcohol metabolism1

You might remember in the last chapter (specifically, Section 6.25), we mentioned that “acetyl- CoA is a central point in metabolism.” This statement is critical to our understanding of metabolism illustrated in the last few figures. Notice that acetyl-CoA is the central metabolite metabolism that connects the many different pathways. For example, carbohydrates (orange pathway) can be broken down to acetyl-CoA that can then be used to synthesize fats and ultimately triglycerides (purple pathway).

References & Links

1. http://en.wikipedia.org/wiki/File:CellRespiration.svg