Question

If a solution of actin is mixed with a solution of myosin, the resulting mixture becomes very viscous. If ATP is added to this viscous mixture, the viscosity is eliminated and ATP is hydrolysed to ADP and inorganic phosphate. The mixture regains viscosity if all the ATP is hydrolysed. These observations suggest that

• A. Actin and myosin bind together
• B. The complex of actin and myosin (actomyosin)
• C. ATP seems to alter the binding between actin and myosin
• D. All of the above

Answer 1

The correct option is D All of the above

Actomyosin is a contractile complex of actin and myosin, that together with ATP, is active during muscular contraction.
Disruption of the myosin-actin interaction requires ATP, while the myosin molecule can hydrolyze ATP into ADP and Pi.
ATP disconnects actin from myosin, after which it is hydrolyzed by the myosin molecule to produce the energy required for muscle contraction.