Hvor mange atp-molekyler der opnås fra glykolyse?
til
Cellular respiration
Glykolyse er en metabolisk vej, der finder sted i cytosolen i cellerne i alle levende organismer. Denne vej kan fungere med eller uden tilstedeværelse af ilt. Hos mennesker dannes der pyruvat under aerobe forhold og laktat under anaerobe forhold. Under aerobe forhold omdanner processen et glukosemolekyle til to molekyler pyruvat (pyrubrinsyre), hvorved der dannes energi i form af to nettomolekyler ATP. Der produceres faktisk fire ATP-molekyler pr. glukose, men to forbruges som led i den forberedende fase. Den indledende fosforylering af glukose er nødvendig for at øge reaktiviteten (mindske stabiliteten), således at molekylet kan spaltes i to pyruvatmolekyler af enzymet aldolase. I glykolysens udbetalingsfase overføres fire fosfatgrupper til ADP ved fosforylering på substratniveau for at fremstille fire ATP, og der dannes to NADH, når pyruvatet oxideres. Den samlede reaktion kan udtrykkes på denne måde:
two
Cellular respiration
Glycolysis is a metabolic pathway that takes place in the cytosol of cells in all living organisms. This pathway can function with or without the presence of oxygen. In humans, aerobic conditions produce pyruvate and anaerobic conditions produce lactate. In aerobic conditions, the process converts one molecule of glucose into two molecules of pyruvate (pyruvic acid), generating energy in the form of two net molecules of ATP. Four molecules of ATP per glucose are actually produced, however, two are consumed as part of the preparatory phase. The initial phosphorylation of glucose is required to increase the reactivity (decrease its stability) in order for the molecule to be cleaved into two pyruvate molecules by the enzyme aldolase. During the pay-off phase of glycolysis, four phosphate groups are transferred to ADP by substrate-level phosphorylation to make four ATP, and two NADH are produced when the pyruvate are oxidized. The overall reaction can be expressed this way:
Cellular respiration