Question

ATPase of the muscle is located in
A. Actinin
B. Troponin
C. Myosin
D. Actin

Answer 1

Hint: ATPase are a group of enzymes that catalyzes the decomposition of ATP into ADP. This dephosphorylation reaction releases energy, which the enzyme harnesses to drive other chemical reactions that would not otherwise occur.

Complete answer: The myosin filament has meromyosin that has two important components; a globular head and a tail. The globular head has the location for ATPase enzyme and has binding sites for ATP. It helps in attaching the actin filament during the sliding motion. The head of the myosin molecule contains an enzyme, i.e. myosin ATPase. In the presence of the enzyme, myosin ATPase, calcium ions, magnesium ions, etc. ATP gets converted into ADP and inorganic phosphate and as a result of which, it releases energy in the myosin head. Though cells can harness polymerization of actin (a protein) to initiate some types of movement, several cell movements rely upon interactions between actin and myosin filaments. The type of enzyme that converts chemical energy into mechanical energy is known as a mechanochemical enzyme or a motor protein. Myosin are motor proteins, and actin filaments are tracks along which myosin moves, and ATP is the fuel that powers the movement of the enzyme.
Hence, the correct answer is option C.

Note: Thirteen members of the myosin protein family have been identified by genomic analysis. Myosin I and myosin II are the most abundant and are present in almost all eukaryotic cells. A less common isoform, i.e. myosin V has been isolated and featured. Although specialized activities of these myosins differ, they all function as motor proteins.