For Crossbridges to Occur,what Events Must Happen? Select All That

Question

For crossbridges to occur,what events must happen? Select all that apply.
A)ATPase breaks down ATP.
B)calcium ions be present in the sarcoplasm.
C)myosin binding sites be exposed.
D)high amounts of sodium be present in the synaptic cleft
E)Acetylcholine be present in the synaptic cleft

Accepted Answer

For crossbridges to form in muscle contraction, ATP must be broken down by ATPase to provide energy (A), calcium ions must be present in the sarcoplasm to initiate the contraction process (B), and myosin binding sites on actin must be exposed, often as a result of the action of calcium ions (C). High amounts of sodium in the synaptic cleft (D) and the presence of acetylcholine in the synaptic cleft (E) are related to the initiation of muscle contraction at the neuromuscular junction, but they are not directly involved in the formation of crossbridges within the muscle fibers themselves.