Question

The cross arm that forms the cross brides during muscle contraction, is formed by

• A. HMM
• B. LLM
• C. Troponin
• D. Both A and C

Answer 1

The correct option is D Both A and C

Troponin is found in muscle and it helps in muscle contraction. It resides on the target when our muscle is in relaxed state .

As the calcium ions reaches the troponin and binds to it , it enables the actin head to bind to the myosin head and thus helps in muscle stroke which results in the contraction of the muscle .HMM is heavy meromysin and it has two subunits namely HMMS-1 and HMMS-2 . HMMS-1 has actin binding site and ATP binding site myosin that determines the rate of muscle contraction when muscle is relaxed . So we can say that the formation of cross arm bridge is due to the troponin present .

So the correct answer is ' both (a) and (c)'