Master Gardener Practice Exam

Photosynthesis harnesses light energy to build sugars from carbon dioxide and water, producing glucose and oxygen. The balanced overall equation is 6 CO2 + 6 H2O -> C6H12O6 + 6 O2. If you count atoms, you have 6 carbon, 12 hydrogen, and 18 oxygen on both sides, so the equation is balanced. The glucose produced is C6H12O6, and the six O2 molecules represent the oxygen gas released. This is the correct direction for photosynthesis: carbon dioxide and water are the inputs, and glucose plus oxygen are the outputs, with light energy driving the reaction. The other options either show the process as the reverse (glucose and oxygen converting to CO2 and water), show no net chemical change (the same molecules on both sides), or are not balanced properly, so they don’t accurately represent the overall photosynthesis equation.