atp production occurs in oxidative phosphorylation in a cell.
atp production occurs in oxidative phosphorylation in a cell.
where does atp production occur in a cell?
oxidative phosphorylation
glycolysis, which means “sugar splitting,” is the initial process in the cellular respiration pathway. glycolysis can be either an aerobic or anaerobic process. when oxygen is present, glycolysis continues along the aerobic respiration pathway. if oxygen is not present, then atp production is restricted to anaerobic respiration. the location where glycolysis, aerobic or anaerobic, occurs is in the cytosol of the cell. in glycolysis, a six-carbon glucose molecule is split into two three-carbon molecules called pyruvate. these carbon molecules are oxidized into nadh and atp. for the glucose molecule to oxidize into pyruvate, an input of atp molecules is required. this is known as the investment phase, in which a total of two atp molecules are consumed. at the end of glycolysis, the total yield of atp is four molecules, but the net gain is two atp molecules. even though atp is synthesized, the two atp molecules produced are few compared to the second and third pathways, krebs cycle and oxidative phosphorylation.
carbohydrate catabolism
at rest, the body produces the majority of its atp aerobically in the mitochondria without producing lactic acid or other fatiguing byproducts. during exercise, the method of atp production varies depending on the fitness of the individual as well as the duration and intensity of exercise. at lower activity levels, when exercise continues for a long duration (several minutes or longer), energy is produced aerobically by combining oxygen with carbohydrates and fats stored in the body. during activity that is higher in intensity, with possible duration decreasing as intensity increases, atp production can switch to anaerobic pathways, such as the use of the creatine phosphate and the phosphagen system or anaerobic glycolysis. aerobic atp production is biochemically much slower and can only be used for long-duration, low-intensity exercise, but produces no fatiguing waste products that can not be removed immediately from the sarcomere and the body, and it results in a much greater number of atp molecules per fat or carbohydrate molecule. aerobic training allows the oxygen delivery system to be more efficient, allowing aerobic metabolism to begin quicker. anaerobic atp production produces atp much faster and allows near-maximal intensity exercise, but also produces significant amounts of lactic acid which renders high-intensity exercise unsustainable for more than several minutes. the phosphagen system is also anaerobic. it allows for the highest levels of exercise intensity, but intramuscular stores of phosphocreatine are very limited and can only provide energy for exercises lasting up to ten seconds. recovery is very quick, with full creatine stores regenerated within five minutes.
muscular system