Coupled reaction

• A. A reaction that occurs without energy transfer
• B. A reaction that releases energy from glucose
• C. A chemical reaction that uses energy independently
• D. When energy require by one process is supplied by another process

Answer: (D)

Energy coupling means using the energy released by one reaction to drive another reaction that needs energy. In biology, cells often pair an exergonic step with an endergonic one, transferring energy through carriers like ATP. So the essence is that energy required by one process is supplied by energy from another process, enabling the endergonic step to proceed. For example, ATP hydrolysis provides the energy to drive biosynthetic reactions, muscle contraction, or active transport. The other options don’t capture this transfer between processes: one describes a process with no energy transfer, another just describes energy release from glucose without coupling, and another implies the reaction would run on its own energy without receiving energy from elsewhere.