Energy Systems in Muscle Cells U1

during strenuous exercise, cells do not get enough oxygen to support the etc only glycolysis is able to provide ATP fermentation occurs due to lack of oxygen pyruvate is converted into lactate in order to produce lactate, the hydrogen from NADH is transferred to pyruvate

build up of lactate causes fatigue and an oxygen debt builds up oxygen debt is repaid and lactate converts back into pyruvate which enters the aerobic pathway

sustain contractions for a long time long distance running, cycling or cross-country skiing aerobic respiration generates ATP many mitochondria large blood supply myoglobin major storage fuel is fats

short contraction time sprinting or weightlifting glycolysis generates ATP fewer mitochondria lower blood supply major storage fuel is glycogen