MICROANATOMY

Detailed explanation-1: -ATP binding causes myosin to release actin, allowing actin and myosin to detach from each other. After this happens, the newly bound ATP is converted to ADP and inorganic phosphate, Pi. The enzyme at the binding site on myosin is called ATPase.

Detailed explanation-2: -ATP binding causes the myosin head to detach from the actin (Figure 4d). After this occurs, ATP is converted to ADP and Pi by the intrinsic ATPase activity of myosin. The energy released during ATP hydrolysis changes the angle of the myosin head into a cocked position (Figure 4e).

Detailed explanation-3: -Hence, the correct answer is (B) ‘When ATP attaches to myosin head’. Note: The binding of ATP results in the release of actin, in this way it allows actin and myosin to become detached from each other. The enzyme that is present at the binding site of myosin is known as ATPase.

Detailed explanation-4: -Step 2: ATP binding to the myosin head domain induces a small conformational shift in the actin-binding site that reduces its affinity for actin and causes the myosin head to release the actin filament.

Detailed explanation-5: -ATP and Muscle Contraction Myosin binds to actin at a binding site on the globular actin protein. Myosin has another binding site for ATP at which enzymatic activity hydrolyzes ATP to ADP, releasing an inorganic phosphate molecule and energy.