If a muscle fiber were to suddenly and permanently stop producing ATP the fiber would no longer be able to actively transport calcium out of the cytoplasm (sarcoplasm) and the intracellular calcium concentration would rise. Which of the following would you expect to happen?
◦ Calcium would be transported to the sarcoplasmic reticulum therefore contractions would cease.
◦ No change would occur in a muscle that was relaxed to begin with.
◦ The fiber would twitch uncontrollably due to excessive calcium bound to troponin.
◦ Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach.
Hand muscle
(A) A neuron connecting to a skeletal muscle.
Structure of a skeletal muscle.
Skeletal muscle
Cardiac muscle