Question

4. W
A.
3. Answer the following questions in detail
A. How is the structure of sarcomere suitable
for the contractility of the muscle?
Explain its function according to sliding
filament theory. (Refer to chapter animal
tissues.)
​

Answer 1

Answer:

1. During contraction, the myosin head gets attached to the active site of actin filaments and pull them inwardly so that the actin filaments slide over the myosin filaments. This results in the contraction of muscle fibre.
2. There are 2 major kinds of proteins in muscles. Actin and myosin. Myosin proteins have portions named head that can interact with actin filaments. When calcium enters the cell after some reactions the active sites of actin are ready for the head of the myosin. Head of the myosin uses an ATP molecule and perform a stroke resulting in sliding of actin over myosin towards the centre. This result in shortening of sarcomere resulting in contraction.

Thus according to this sliding theory actin and myosin helps in muscle contraction and help in the movements of joints.