Question

Identify the correct sequence of the following events. a. Myosin generates a power stroke. b. Ca++ binds to troponin. c. ATP recharges the myosin head. d. Troponin removes tropomyosin from G actin. e. The sarcomere shortens. f. Myosin binds to actin.

Answer 1

Answer:

Ca+ binds to troponin

Troponin removes tropomyosin from G actin

Myosin binds to actin

Myosin generates a power stroke

The sarcomere shortens

ATP recharges the myosin head

Explanation:

Contraction begins with the release of calcium ions into sarcoplasm where they bind to troponin. It moves the tropomyosin always from the myosin-binding sites present on actin. Myosin head binds to actin and forms cross-bridge followed by power stroke in which myosin head pivots to pull the thin filament past the thick filament towards the center of the sarcomere and results in shortening of the sarcomere. The myosin head binds to ATP and the cross-bridge detaches from actin. Hydrolysis of ATP charges myosin head again.