ANATOMY

Detailed explanation-1: -Both calcium & magnesium are required for muscle contraction. Calcium binds to troponin which exposes the active sites on actin. Now myosin head can bind the active sites on actin, initiating the process of muscle contraction. The hydrolysis of ATP is used to provide energy for muscle contraction.

Detailed explanation-2: -The contraction of skeletal muscles is an energy-requiring process. In order to perform the mechanical work of contraction, actin and myosin utilize the chemical energy of the molecule adenosine triphosphate (ATP).

Detailed explanation-3: -Calcium and ATP are cofactors (nonprotein components of enzymes) required for the contraction of muscle cells.

Detailed explanation-4: -(1) Calcium binds to troponin C, causing the conformational shift in tropomyosin that reveals myosin-binding sites on actin. (2) ATP then binds to myosin. (3) ATP is then hydrolyzed. (4) A cross-bridge forms and myosin binds to a new position on actin.

Detailed explanation-5: -Calcium and adenosine triphosphate (ATP) has a crucial significance in powering or forcing muscle contraction activity. The contraction cycle of the muscles is induced by the calcium ions that significantly attach to a specialized protein complex, troponin, and thereby free the active-binding regions of the actin.