Select the correct statements regarding the mechanism of muscle contraction. A. During muscle contraction, the 'I' bands get reduced, whereas the 'A' bands retain their length. B. The globular head of myosin is an active ATPase enzyme and has binding sites for ATP and active sites for troponin. C. A motor neuron along with the muscle fibres connected to it constitute a motor unit. D. Binding of a new ATP molecule to

Step-by-step solution

Statement A is correct. During muscle contraction, the actin filaments slide over the myosin filaments, causing the 'I' band to shorten while the 'A' band retains its length. Statement B is incorrect. The globular head of myosin is an active ATPase enzyme and has binding sites for ATP and active sites for actin, not troponin. Statement C is correct. A motor neuron along with the muscle fibres connected to it constitute a motor unit. Statement D is incorrect. The binding of a new ATP molecule to the myosin head lead