The ATPase activity of the myosin head is dependent on:

1. Magnesium ions

2. Manganese ions

3. Calcium ions

4. Ferric ions

The binding of troponin on actin Filaments actually unmasks the …..

1. Active site for Tropomyosin

2. Active site for ATP

3. Active site for Myosin

4. Active site for troponin

Contractile unit of muscle is part of myofibril between

1.  Z-line and l-band

2.  Z-line and Z-line

3.  Z-line and A-band

4.  A-band and l-band 

The binding of calcium to troponin actually indicates

1. Unmasking of Myosin binding site over meromyosin

2. Unmasking of Myosin binding site over actin

3. Unmasking of the actin-binding site over Myosin

4. Unmasking of actin-binding site over tropomyosin

Which of the following statements is incorrect?

1. A new ATP binds and cross-bridge is broken with the next cycle of contraction

2. The process of contraction continues till the calcium ions are pumped back to the sarcoplasmic cisternae and resulting in the unmasking of actin Filaments

3. The reaction time of the fibres can vary in different muscles

4. Both 1 and 3