Which of the following processes directly require ATP? Choose all that apply.

a. Diffusion of calcium into the motor neuron at the neuromuscular junction.
b. Release of cross-bridge (interaction) between actin and myosin.
c. Movement of calcium ions back into the sarcoplasmic reticulum after contraction.
d. Conformation change of troponin resulting in the movement of tropomyosin off the actin active sites.

the following processes directly require ATP includes:

B (Release of cross-bridge (interaction) between actin and myosin.)

C (Movement of calcium ions back into the sarcoplasmic reticulum after contraction.)

Explanation:

Muscle contraction occurs in various parts of the body to ensure proper body functioning. This process requires the release of calcium ion and the use of ATP ( Adenosine Triphosphate) as source of energy at various levels for the process to take place. The distinct role of ATP in muscle contraction includes:

-ATP is directly required as it causes detachment from actin after power stroke when it binds at one of the reactive sites of myosin. This explains option B (Release of cross-bridge (interaction) between actin and myosin.)

-it powers the pump that transports calcium ions back into the sarcoplasmic reticulum after contraction. This explains option C (Movement of calcium ions back into the sarcoplasmic reticulum after contraction)

- it activates the myosin head so it can bind to actin and rotate by the action of ATpase enzyme.