Which statement about mechanical work powered by ATP is correct?

Which statement about mechanical work powered by ATP is correct?

• A. Mechanical work moves muscles
• B. Mechanical work is energy stored in fats
• C. Mechanical work occurs only in plants
• D. Mechanical work refers to building membranes

Answer: (B)

ATP provides the energy that cells use to do mechanical work, such as causing movement or contraction. In muscle cells, ATP hydrolysis powers the myosin motor to pull on actin filaments, producing muscle contraction—this is the classic example of mechanical work in biology. Energy stored in fats is chemical energy that must first be released and converted into ATP; it isn’t itself mechanical work. Mechanical work isn’t limited to plants; animals and other organisms perform movement and transport as well. Building membranes is a biosynthetic, chemical process that uses ATP, but it isn’t mechanical work like moving muscles. So the statement that mechanical work moves muscles best captures the direct, observable effect of ATP-powered mechanical energy.

ATP provides the energy that cells use to do mechanical work, such as causing movement or contraction. In muscle cells, ATP hydrolysis powers the myosin motor to pull on actin filaments, producing muscle contraction—this is the classic example of mechanical work in biology. Energy stored in fats is chemical energy that must first be released and converted into ATP; it isn’t itself mechanical work. Mechanical work isn’t limited to plants; animals and other organisms perform movement and transport as well. Building membranes is a biosynthetic, chemical process that uses ATP, but it isn’t mechanical work like moving muscles. So the statement that mechanical work moves muscles best captures the direct, observable effect of ATP-powered mechanical energy.