Question

3:097 Exit The structure that allows action potentials to propagate into skeletal muscle is called a Sarcoplasmic reticulum T-tubule Sarcomere Sarcoplasm D 2. Select the best answer. Each myosin head has a bind site for ATP only Actin only Calcium only Calcium and ATP Actin and ATP D 3. Which of the following molecular events comes first when we want to contracta skeletal

Answer 1

1.

The structure that allows action potential to flow through the skeletal muscles is T-tubule.

During muscle contraction mechanism, when an Action potential is generated T-tubules activate L-type calcium channels allowing Ca to pass through the cell as they have a higher concentration of L-type receptors in T-tubules than in rest of the sarcolemma.

The other options:

Sarcoplasmic reticulum of muscle fibres is the store house of calcium ions.

Sarcomere is the functional unit of muscle contraction and its the portion of the myofibril between two successive Z-Lines.

Sarcoplasm is the cellular content of the muscle cells surrounded by the sarcolemma

2.

Each myosin head has a binding site for ATP only.

The globular head of myosin is an active ATPase enzyme and has binding sites for ATP.

The other options:

Calcium binds with the subunit of troponin on actin filaments.

Myosin heads does not have the binding sites for actin rather actin heads have the binding sites for myosin which are masked by a subunit of troponin.