grana

/ˈɡrɑːnə/
noun
  1. The plural of granum; stacks of thylakoid membranes inside plant chloroplasts where photosynthesis occurs.
    • Under the microscope, the grana appear as dark green stacks within the chloroplasts.
    • Photosynthesis takes place in the grana of the chloroplast.
    • The number of grana in a chloroplast can vary depending on the plant species.