Kataboolsed

Kataboolsed, or catabolic processes, are metabolic pathways that break down complex molecules into simpler ones, releasing energy in the process. The term derives from Greek katabole, meaning throwing down. In contrast to anabolic processes, which build up molecules, catabolic reactions provide energy and substrates for biosynthesis.

Key catabolic pathways include glycolysis, the citric acid cycle, oxidative phosphorylation, beta-oxidation of fatty acids, proteolysis, and autophagy. In eukaryotic cells these steps occur in the cytosol, mitochondria, or lysosomes. The energy released is captured in high-energy carriers such as ATP, NADH, and FADH2 and used to power cellular work and to provide building blocks for anabolic pathways.

Regulation of catabolism is closely tied to the cell’s energy status. AMPK acts as a major energy sensor that promotes catabolic pathways during energy shortage. Hormonal signals influence catabolism as well: glucagon and adrenaline stimulate the breakdown of glycogen and fats, while insulin generally suppresses catabolic processes in favor of growth and storage.

Physiological and clinical relevance: catabolism is essential for energy production, adaptation to fasting and exercise, and turnover of macromolecules. Dysregulation of catabolic processes can contribute to muscle wasting, cachexia, and metabolic diseases when the balance with anabolism is impaired.