The light stage of photosynthesis occurs in the thylakoid membranes of chloroplasts and requires light energy and water. During this stage, light energy is captured and converted into chemical energy in the form of ATP and NADPH, with oxygen gas released as a byproduct. In contrast, the dark stage (also known as the Calvin cycle) takes place in the stroma of chloroplasts and does not directly require light. It utilizes the ATP and NADPH produced during the light stage, along with carbon dioxide, to synthesize glucose (sugars). That's 2 down. 3 left today — send the next one.