You Have Used "Optical Tweezers" to Study the Mechanics of Myosin

question 36

Short Answer

You have used "optical tweezers" to study the mechanics of myosin movement in a newly discovered member of the myosin II subfamily. Your results indicate that each myosin exerts a force of about 3 pN along the length of the actin filament, and displaces the filament by about 10 nm in each cycle of ATP hydrolysis. Assuming that the free-energy change for ATP hydrolysis is -50 kJ/mol under your experimental conditions, what is the efficiency of the myosin motor in converting the free energy to mechanical work? Remember that under a constant force F (in newtons), work (W; in joules) is calculated as W = F × d, where d is displacement (in meters) in the direction of the force. Avogadro's number is approximately 6 × 10²³ molecules/mole. Write down your answer as a percentage with no decimals, e.g. 99%.

---

Definitions:

Investment Center

An investment center is a business unit within an organization that has control over its revenues, expenses, and investments, and is evaluated based on its return on investment.

Franchise Fee

An initial payment made by a franchisee to a franchisor for the rights to use the franchisor's brand, system, and ongoing support.

Percent

A measure or ratio expressed as a fraction of 100.

Patent

A legal right granted by the government to an inventor, granting exclusive use of an invention for a certain period of time, preventing others from making, using, or selling the invention without permission.