University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

78

Pages:

2
Author:

Mariam A. A.

Aerobic vs Anaerobic Aerobic • • • • • • • Introducing O2 activates the citric acid cycle, raises [ATP], inhibits PFK and pyruvate kinase, and slows glycolysis. Under aerobic conditions, cells containing mitochondria typically convert most of the pyruvate they generate from carbohydrate metabolism to acetyl CoA, rather than to lactate. Thus, it yields a net gain of two NADH molecules per glucose molecule. The oxidative phosphorylation of each NADH molecule will yield 1.5 or 2.5 ATP molecules, depending on which shuttle system the cell uses to transfer the reducing equivalents from the cytosol into the mitochondria. Therefore, under aerobic conditions, glycolysis of one glucose molecule generates two ATP molecules directly plus three or five ATP molecules through the oxidative phosphorylation of the two NADH molecules, for a total of five or seven ATP molecules per glucose molecule. Sources of aerobic metabolism are carbohydrates, fat, and metabolism The final common pathway of aerobic catabolism releases CO2, H2O, ATP, and heat. Anaerobic • • • • • • • • • Oxygen is not used as a reactant Glycolysis—which takes place in the cytosol—yields two lactate molecules plus two ATP molecules per glucose molecule This process is not very efficient in comparison to aerobic respiration Under anaerobic conditions, cells convert pyruvate to lactate, accompanied by the accumulation of H+ (lactic acidosis). Thus, sustained skeletal muscle activity depends on the aerobic metabolism of pyruvate as well as fat Occurs in cytoplasm/cytosol As a result, fatigue onset is rapid as the H+ build up affects actin-myosin interactions and causes pain by irritating sensory nerves Anaerobic energy sources are carbohydrates (glucose and glycogen) Anaerobic sources of ATP in maximal performances last two minutes or less • Short-term anaerobic races shouldn't be affected by the low P02 at altitude because 02 transport to the muscles is not limiting performance