Metabolism is the overall process through which living systems acquire and utilize the free energy they need to carry out their various functions. They do so by coupling the exergonic reactions, or spontaneous reactions, of nutrient oxidation to the endergonic processes, or nonspontaneous processes that require the use of free energy, required to maintain the living state such as the performance of mechanical work, the active transport of molecules against concentration gradients, and the biosynthesis of complex molecules.
Glycolysis is the metabolic pathway by which glucose is converted via fructose-1,6-bisphosphate to pyruvate with the generation of 2 mol of ATP/mol of glucose. This sequence of 10 enzymatic reactions plays a key role in energy metabolism by providing a significant portion of the energy utilized by most organisms and by preparing glucose, as well as other carbohydrates, for oxidative degradation.
Glucose, a major metabolic fuel source, is degraded via glycolysis to produce ATP. Higher organisms protect themselves from potential fuel shortage by polymerizing excess glucose for storage as high molecular mass glucans (glucose polysaccharides) that may be readily mobilized in times of metabolic need. In plants this glucose storage substance is starch, while in animals the storage glucan is glycogen. Glycogen metabolism is the metabolic pathways that break down glycogen into glucose to be used by the cell.
The citric acid cycle is the common mode of oxidative degradation in eukaryotes and prokaryotes. This cycle, which is alternatively known as the Tricarboxylic acid cycle (TCA) or the Krebs cycle, marks the "hub" of the metabolic system: it accounts for the major portion of carbohydrate, fatty acid, and amino acid oxidation and generates numerous biosynthetic precursors. The citric acid cycle is therefore amphibolic, that is, it operates both catabolically and anabolically.
Energy from food
Your body gets the energy it needs from food through a process called metabolism. 
- The reason for this being in the wrong topic is that biochemical metabolism is about certain types or molecules being used in metabolic processes. This would fit better in digestion where the digestive track breaks food down to finer particles that can be further broken down for use in cellular metabolism. In other words it would be like inserting how the nervous system works in an article about cellular signaling.--Able806 14:26, 17 April 2008 (EDT)