Question

Rigor mortis is a stiffening of the body that occurs when muscle cells are unable to relax after a contraction. Why does rigor mortis occur after death?

Answer 1

Rigor mortis occurs after death due to the absence of ATP, which is needed for muscle relaxation. Without ATP, myosin heads cannot detach from actin-binding sites, leading to muscle stiffness.

Step-by-step explanation:

Rigor mortis occurs after death because of the absence of ATP, which is necessary for muscle relaxation. During muscle contraction, ATP binds to myosin heads and allows them to detach from actin-binding sites, resulting in muscle relaxation.

However, after death, ATP production ceases, and there is no ATP available for myosin heads to detach from the actin-binding sites. As a result, the cross-bridges between myosin and actin filaments remain in place, causing muscle stiffness or rigor mortis.