Question

Explain how skeletal muscle contracts ib biology

Answer 1

Answer and explanation;

Contraction of skeletal muscles;

-An action potential from a motor neuron triggers the release of Ca2+ ions from the sarcoplasmic reticulum.

-Calcium ions expose the myosin heads by binding to a blocking molecule (troponin complexed with tropomyosin) and causing it to move.

-The myosin heads form a cross-bridge with actin binding sites.

-ATP binds to the myosin heads and breaks the cross-bridge.

-The hydrolysis of ATP causes the myosin heads to change shape and swivel - this moves them towards the next actin binding site.

-The movement of the myosin heads cause the actin filaments to slide over the myosin filaments, shortening the length of the sarcomere.

-Via the repeated hydrolysis of ATP, the skeletal muscle will contract.