Catabolism

Lore & Background

Catabolism breaks down large molecules such as polysaccharides, lipids, nucleic acids, and proteins into smaller units like monosaccharides, fatty acids, nucleotides, and amino acids. Cells use these monomers to construct new polymers or degrade them further into simple waste products, releasing energy. Cellular wastes include lactic acid, acetic acid, carbon dioxide, ammonia, and urea, and their formation is usually an oxidation process that releases chemical free energy, some lost as heat, but the rest used to drive ATP synthesis.

Reader's Guide

Catabolism is a destructive metabolism that provides the chemical energy necessary for the maintenance and growth of cells. It is the counterpart to anabolism, which is constructive metabolism. Examples of catabolic processes include glycolysis, the citric acid cycle, the breakdown of muscle protein for gluconeogenesis, the breakdown of fat in adipose tissue to fatty acids, and oxidative deamination of neurotransmitters by monoamine oxidase. The word catabolism comes from Neo-Latin, with Greek roots meaning 'downward' and 'to throw'.

Did You Know?

• Catabolism breaks down polysaccharides, lipids, nucleic acids, and proteins into monosaccharides, fatty acids, nucleotides, and amino acids.
• Cellular wastes from catabolism include lactic acid, acetic acid, carbon dioxide, ammonia, and urea.
• Classic catabolic hormones include cortisol, glucagon, and adrenaline.
• The word catabolism derives from Greek roots meaning 'downward' and 'to throw'.