In plants, where do light-dependent reactions of photosynthesis occur?

The light-dependent reactions of photosynthesis occur in the granum, which is a stack of thylakoids found within the chloroplasts of plant cells. During these reactions, chlorophyll absorbs light energy, which is then converted into chemical energy in the form of ATP and NADPH.

Thylakoids, which are membrane-bound compartments, contain the chlorophyll that captures light energy. When light is absorbed, it initiates a series of reactions that ultimately lead to the production of the energy carriers, but it's important to note that the thylakoids themselves are arranged into stacks called granum. Therefore, the granum is the specific structure where these processes effectively take place as it includes multiple thylakoid membranes that enhance the plant's ability to capture light energy efficiently.

The stroma is the fluid-filled space surrounding the thylakoids, where the light-independent reactions (Calvin cycle) occur; this is separate from the light-dependent processes. The thylakoid space refers to the internal space of the thylakoid, playing a role in establishing a proton gradient during the light reactions, but it is not the site of the entire reaction process. Chlorophyll is the pigment that absorbs light, not a location