Biology 2601A/B Lecture : organismal phys.
Document Summary
Metabolism: atp is the main energy source in the cell. Some is produced in glycolysis, but the main products of the citric acid cycle are fadh2 and nadh. In most animals, energy is not stored as atp. It is stored as lipids, carbs (starch, fructans, sucrose in plants, trehalose in insects, and glycogen in animals), and proteins and amino acids. These things contain chemical potential energy that needs to be turned into work. This chemical potential is released by controlled oxidation. Direct burning has a large ea and all the energy is released as heat and none is used for work. Respiration, however, uses small ea s and the energy is transferred to energy carriers in a bunch of small steps. General process: substrate pyruvate/acetyl coa krebs cycle mitochondrial etc (last two steps happen in the mitochondria). Cells with lots of mitochondria do lots of work. When oxygen is available, the fuel (glucose) is broken down using glycolytic pathways.