Just like chloroplasts gardeners have to have a method to grow food for the castle. Instead of using photosynthesizes they crop, water and use sunlight to grow their vegetables.
Link to the picture : http://www.psumedievalgarden.com/graphics/october_medieval_gardening.jpg
Lysosomes to Catapult
Catapults are necessary to fend off attacking enemies. Like lysosomes a catapult breaks down things with the big boulder. If a mess is made, which will happen, the people have been controlling the catapult will clean up.
Link to the picture : http://thumbs.dreamstime.com/z/catapult-reconstruction-medieval-against-red-tower-kizil-kule-alanya-castle-31987615.jpg
Golgi Body to Town Crier
The king has required for the town crier to announce information to the public. This information would probably be important. Like a Golgi body.
Link to the picture : http://www.blogcdn.com/www.stylelist.com/media/2013/07/town-crier.jpg
Ribosomes to Serfs
The king needs his veggies so he orders the serf to collect them. The serfs go to the farm to collect veggies. He gives them to the the cooks ( mitochondria ) so that they can make food and give The King his food/ energy.
Link to the picture : http://athycollegehistory.weebly.com/uploads/1/1/4/3/11438771/6493335.jpg
Mitochondria to The Cooks
The Cooks in the castle keep the king and everyone else in the castle nice, healthy, and full as a pig. The cook gets its food from the gardener ( chloroplasts ).
Link for the picture : https://s-media-cache-ak0.pinimg.com/236x/5f/cb/0e/5fcb0e5623e3497fd32be59a7cb48578.jpg
Nucleus to The King
In a castle there is always a King who rules the castle just like a nucleus. He orders what is going to happen and when it's going to happen. The king is a main reason for the continuous growth of the castle.
Link for the picture : http://www.neuschwanstein.de/bilder/ludwig/ludwig_01_600.jpg
