Question

Which of the following will occur if ATP is not available?

O
Ach will not bind to Ach receptors on the sarcolemma and the sarcolemma will not experience an action potential
(electrical signal).
O Ach will not be released
myosin heads will stay attached to actin
O Ca2+ will not be released from the terminal cisternae

Answer 1

If ATP is not available, Ach will not bind to Ach receptors, Ach will not be released, myosin heads will stay attached to actin.

Step-by-step explanation:

If ATP is not available, several things will occur:

1. Ach will not bind to Ach receptors on the sarcolemma and the sarcolemma will not experience an action potential (electrical signal). ATP is needed to pump calcium ions out of the muscle cell after contraction, which allows for relaxation and prevents continuous muscle contraction.
2. Ach will not be released. ATP is required for the release of Ach (acetylcholine), a neurotransmitter that stimulates muscle contraction.
3. Myosin heads will stay attached to actin. ATP is necessary for breaking the cross-bridge between the myosin heads and actin during muscle contraction. Without ATP, the myosin heads cannot detach from actin, resulting in muscle stiffness.

Learn more about Effect of ATP availability on muscle function