Q.The protein present in the thin filament is
a. myosin
b. actin
c. pectin
d. leucin

Muscle contraction depends on two contractile proteins and two regulatory proteins organised into the sarcomere's filaments.

Thick filaments are bundles of myosin molecules. Each myosin molecule has a globular head (bearing an actin-binding site, an ATP-binding site, and ATPase activity) attached via a flexible hinge to a long tail; the head-bearing short arm is the heavy meromyosin (HMM) and the tail is the light meromyosin (LMM). Myosin molecules bundle together with heads projecting from opposite ends of the filament. …