If SERCA is not functioning in a myoblast,which of the following may occur?
A) Myosin will not undergo the conformational change that results in the power stroke.
B) Myosin will not be able to bind to the thin filament.
C) The myofibrils can shorten but not lengthen.
D) The myofibrils can lengthen but not shorten.

Question

Quizplus · Accepted Answer

SERCA pumps calcium ions from the cytoplasm into the sarcoplasmic reticulum during muscle relaxation. Without SERCA, the cytoplasmic calcium concentration will remain high, and the muscle fibers will contract and become tetanic. As a result, the myofibrils can shorten but not lengthen since the thick and thin filaments will remain locked in the cross-bridge cycle. Therefore, option C is the best choice.

If SERCA Is Not Functioning in a Myoblast,which of the Following