Rigor mortis: why ATP matters
Rigor mortis develops after death because:
Answer B: explanation for every choice
A
After death, calcium leaks into the cytosol and exposes binding sites, so cross-bridges form.
B
Correct. ATP binding releases myosin from actin. Without ATP, cross-bridges stay locked.
C
If binding sites were covered, myosin could not attach, and muscles would be relaxed, not rigid.
D
Nerve signaling stops after death.
TakeawayATP is needed to release myosin from actin, not just to power the stroke.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb101.