Final answer:
ATP synthases in chloroplasts are located on the thylakoid membrane, where they utilize the electrochemical gradient created by the photosynthetic process's electron transport chain to produce ATP.
Step-by-step explanation:
The ATP synthases in chloroplasts are located on the thylakoid membrane. Specifically, they are found in the membrane that encloses an internal space called the thylakoid lumen. During the process of photosynthesis, the energy from sunlight is captured by chlorophyll and used to extract electrons from water, initiating the electron transport chain in the chloroplast. As electrons move through the chain, protons are pumped into the thylakoid lumen, creating an electrochemical gradient. ATP synthase harnesses this gradient to produce ATP, a process called chemiosmosis.