1. Light-dependent reactions: This stage occurs in the thylakoid membranes of chloroplasts and uses light energy to produce ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).

2. Light-independent reactions (Calvin cycle): This stage occurs in the stroma of chloroplasts and uses the ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose.

However, you could also break down photosynthesis into three parts, including the capture of light energy as the first stage. This makes more sense in the context of the overall process, as it's the initial step that allows the other two stages to occur:

1. Light absorption: Pigments like chlorophyll capture light energy from the sun.

2. Light-dependent reactions: This stage uses the absorbed light energy to produce ATP and NADPH.

3. Light-independent reactions (Calvin cycle): This stage uses the ATP and NADPH to convert carbon dioxide into glucose.

So, depending on how you define "parts," you could consider either two or three stages of photosynthesis.