What are the main structures of chloroplasts?

Answer 1

Grana and stroma. Grana are stacks of thalakoid membranes and the stroma is the semiviscous fluid that surrounds the grana. The thylakoid membranes are where the light dependent reactions occur. They produce the energy (ATP and NADPH) which is used in the stroma by the Calvin Cycle (light independent reaction) to fix CO2 and produce sugars. The two processes convert light energy from the sun into chemical energy for use by photosynthetic organisms.

Answer 2

The chloroplast has an inner and outer membrane with an empty intermediate space in between. Inside the chloroplast are stacks of thylakoids, called grana, as well as stroma, the dense fluid inside of the chloroplast. These thylakoids contain the chlorophyll that is necessary for the plant to go through photosynthesis