The light-dependent phase of photosynthesis takes place in the thylakoid membranes of the chloroplasts within plant cells.

Here's why:

* Thylakoids: These are flattened, disc-shaped sacs that are stacked into structures called grana. They are the sites of the light-dependent reactions.

* Chloroplasts: These are organelles within plant cells where photosynthesis takes place. They contain chlorophyll, which absorbs light energy.

* Light-Dependent Reactions: These reactions require light energy to convert light energy into chemical energy in the form of ATP and NADPH.

So, to summarize, the light-dependent phase occurs specifically within the thylakoid membranes inside the chloroplasts of plant cells.