Final answer:
Grana and thylakoids are structural components of chloroplasts, which are responsible for conducting photosynthesis in plant cells.
Step-by-step explanation:
Grana and thylakoids are structural components of chloroplasts, which are organelles found in plant cells. Chloroplasts are responsible for conducting photosynthesis, the process by which plants convert sunlight into energy. Thylakoids are disc-shaped structures within the chloroplast that contain chlorophyll, the pigment responsible for capturing light energy. These structures are stacked to form grana, which increase the surface area available for photosynthesis.