metabolismreaktioner

Metabolismreaktioner are the chemical reactions that sustain life by transforming energy and matter within living organisms. They are organized into metabolic pathways that convert nutrients into energy and precursors for macromolecules, while enabling waste removal. Reactions are catalyzed by enzymes and are regulated to meet cellular demands.

These reactions are generally classified into catabolic pathways, which break down substrates to release energy, and anabolic pathways, which synthesize complex molecules from smaller units. Common reaction types include hydrolysis, condensation, redox reactions, and group transfer reactions such as phosphorylation, acetylation, and aminoacylation. Other processes include isomerization, ligation, decarboxylation, and carboxylation.

Energy carriers such as ATP, NADH, NADPH, and FADH2 power metabolism reactions. ATP provides immediate energy; NADH and FADH2 carry electrons to the electron transport chain in respiration, while NADPH supplies reducing power for biosynthesis. In eukaryotes, many steps occur in organelles such as mitochondria and cytosol, reflecting compartmentalization of metabolism.

Regulation of metabolism is achieved through enzyme activity control, allosteric effects, feedback inhibition, substrate availability, and hormonal signals. Cells balance flux through pathways to maintain homeostasis and adapt to nutritional state and stress.

Examples of major metabolism reactions and pathways include glycolysis, gluconeogenesis, the citric acid cycle, and oxidative phosphorylation; fatty acid oxidation and synthesis; amino acid catabolism and biosynthesis; and nucleotide metabolism. Disruptions in metabolism are linked to diseases and aging, and metabolic engineering aims to optimize pathways for biotech applications.