Anabolic and catabolic pathways
A protein which catalyses or speeds up a chemical reaction. control metabolic pathways. The enzymes change the A substance on which enzymes act. at each step in the metabolic pathway in order to get the final product at the end.
There are different types of metabolic pathways:
- anabolic – this type of pathway requires energy and is used to build up large molecules from smaller ones (biosynthesis).
- catabolic – this type of pathway releases energy and is used to break down large molecules into smaller ones (degradation).
An example of an anabolic reaction is the synthesis of glycogen from glucose.
An example of a catabolic reaction is the process of food digestion, where different enzymes break down food particles so they can be absorbed by the small intestine.
Metabolic pathways can be reversible or irreversible. Almost all pathways are reversible.
If a specific enzyme or substrate isn’t available in a pathway then sometimes an end product can still be made using an alternative route (another metabolic pathway). This might take longer but still results in the end product that is needed.