In plant cells, what are the stacked disks called that are involved in photosynthesis?

The stacked disks involved in photosynthesis in plant cells are referred to as grana, which are structures found within the chloroplasts. Each stack of these disk-like structures is specifically called a granum (plural: grana). These thylakoid membranes within the grana contain chlorophyll and other pigments that are essential for capturing light energy during the process of photosynthesis.

Thylakoids are the individual membrane-bound compartments where light reactions occur, which are part of each granum, but when referring to the stacked structures as a whole, "grana" is the appropriate term. Plastids is a broader category of organelles, including chloroplasts, but does not specifically refer to the stacked disks related to photosynthesis.

Understanding the distinction between these terms is crucial, as it highlights the hierarchical organization of structures in plant cells and emphasizes the role of grana in the successful capture of light energy for photosynthesis.