Biology / Unit 13 Bio 3121 short lesson, about 20 seconds
ATP's Three Roles in Muscle Contraction
Captions available
The idea
ATP, per Bio 0508, powers contraction three ways: energizing the myosin head, detaching myosin from actin after the power stroke, and pumping calcium back into storage.
In practice
Without ATP to detach myosin, a muscle stays locked in contraction — the mechanism behind rigor mortis.
Where people slip
ATP relaxes a muscle as much as it contracts one, against picturing ATP as only a "go" signal.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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