Final answer:
The statement in question is false as chloroplasts are indeed involved in ATP synthesis during the light-dependent reactions of photosynthesis, in addition to fixing CO₂ in the Calvin cycle.
Step-by-step explanation:
The statement 'ATP synthesis occurs in the mitochondria but not in the chloroplast. The chloroplast only fixes CO₂' is false. Both mitochondria and chloroplasts are involved in ATP synthesis. In mitochondria, ATP is produced during cellular respiration. Specifically, the electron transport chain and ATP synthase enzyme in the inner mitochondrial membrane participate in ATP synthesis. Meanwhile, chloroplasts are where photosynthesis occurs in plant cells. The process of photosynthesis includes the light-dependent reactions in the thylakoid membranes, which generate ATP and NADPH. The Calvin cycle, which occurs in the stroma, then uses this ATP and NADPH to fix CO₂ into the sugar molecule GA3P. Therefore, chloroplasts not only fix CO₂ but also synthesize ATP as part of the photosynthetic process.