Metabolizam

Metabolizam, or metabolism, is the set of life-sustaining chemical reactions in organisms that convert nutrients into energy and building blocks for growth and maintenance. It encompasses the entire network of biochemical transformations, including energy production, synthesis of macromolecules, and waste removal. Energy is captured mainly in the molecule adenosine triphosphate (ATP) and used to power cellular processes.

Metabolism is commonly divided into catabolism, the breakdown of larger molecules into smaller ones with energy release, and anabolism, the synthesis of complex molecules from simpler ones, which consumes energy. Enzymes catalyze nearly all metabolic reactions, with cofactors aiding redox reactions, group transfers, and bond formation. Pathways are integrated and regulated to meet the cell’s needs and to maintain homeostasis. Hormones, allosteric control, and gene expression coordinate flux through pathways.

Basal metabolic rate (BMR) represents the energy needed to maintain basic functions at rest, while total energy expenditure includes activity and environmental demands. Metabolism is influenced by age, sex, body composition, nutrition, temperature, and genetics. In plants, primary metabolism includes photosynthesis and respiration, while microbes exhibit diverse catabolic and anabolic networks.

Common metabolic pathways include glycolysis, the citric acid cycle, and oxidative phosphorylation for energy production, as well as biosynthetic routes for carbohydrates, lipids, proteins, and nucleotides. Disruptions can lead to metabolic disorders, such as diabetes, obesity, or inborn errors of metabolism, which may affect energy balance and growth. Metabolizam is studied through metabolic profiling, calorimetry, and systems biology to understand health and disease.