Multiple choice What are the flattened discs like structures present in golgi apparatus known as? Grana Cisterns Stroma Vacuoles Reveal answer Fill a bubble to check yourself B Correct answer Explanation The Golgi apparatus consists of stacked, flattened membrane-bound sacs called cisternae (cisterns). Grana are stacks of thylakoids in chloroplasts, stroma is the fluid in chloroplasts, and vacuoles are storage organelles.