8.10: Dietary Connections
Organisms also ingest food in the form of carbohydrates, proteins, and lipids, which also play a role in the glycolysis pathway.
Carbohydrates, Proteins, and Lipids
Carbohydrates—chains of many simple sugars—are first broken down into smaller units and fed into the glycolysis pathway, where they are then broken down into pyruvate. For example, sucrose—a sugar found in most fruits and vegetables—is broken down into two simpler sugars, fructose and glucose, and then catabolized in the glycolytic pathway.
Proteins—via enzymes—are broken down into amino acids, and while some amino acids are recycled to build new proteins, others can enter the glycolytic pathway at different points, only after the amine group is removed and converted into ammonia.
Lastly, lipids—in the form of cholesterol and triglycerides—are catabolized in a process called beta-oxidation: the fatty acid chains are converted into acetyl groups, which are then picked up by the CoenzymeA and enter the pathway through the citric acid cycle.