A poison that caused muscle cells to remain in a contracted state could act by preventing the

Question

Quizplus · Accepted Answer

Muscle contraction is initiated by the release of calcium ions (Ca^2+) from the sarcoplasmic reticulum into the cytosol. These ions bind to troponin, causing a conformational change that moves tropomyosin away from the binding sites on actin, allowing myosin to bind to actin and initiate contraction. For muscles to relax, Ca^2+ must be actively transported back into the sarcoplasmic reticulum. A poison that prevents the return of Ca^2+ to the sarcoplasmic reticulum would keep the muscle in a contracted state because the calcium ions would remain in the cytosol, continuously allowing myosin to bind to actin.

A Poison That Caused Muscle Cells to Remain in a Contracted