Science · Week 4
Light energy, glucose, and the flow of energy in ecosystems.
Photosynthesis: carbon dioxide + water + light → glucose + oxygen. It happens in chloroplasts.
The light-dependent reactions split water and store energy in ATP and NADPH. The Calvin cycle uses that energy to build sugar.
Respiration is the reverse idea: cells break sugar to make ATP. Producers capture energy; consumers eat to get it.
Food webs show energy moving from the sun → producers → consumers → decomposers, with energy lost as heat at each step.