Petri Dish

We are currently working on Petri Dish, an educational game that simulates the growth of bacteria cells and colonies. Players design a bacteria cell by selecting the proteins that the cell can produce and determining how the production and activity of those proteins are regulated, and then iterate on their design by setting the cell loose in different chemical environments and studying how it does.

Much of the learning in Petri Dish is immersive. Simply by living in this world, players observe that:

• molecules are created by building up or breaking down other molecules;
• chemical reactions occur along metabolic pathways;
• each step in a reaction pathway is mediated by a protein that uses energy;
• proteins are assembled out of amino acids;
• nucleic acids are assembled out of nucleotides;
• reaction rates are proportional to the concentration of the reactants; and
• a cell duplicates its nucleic acids to reproduce through binary fission.

To design a bacteria cell that thrives in its environment, the player must analyze the metabolic network and determine how the cell should prioritize the production of energy, amino acids, and nucleotides. Since all three metabolic pathways are linked and share common intermediates, the production of energy, amino acids, and nucleotides must be balanced to optimize the growth of the cell. Metabolic pathways are regulated on two levels: (1) through feedback inhibition on the protein itself, and (2) through gene expression. Players will start by regulating the metabolic pathways in a single cell manually, but will eventually program the cell to operate autonomously and form a multicellular bacteria colony.

Along the way, players discover how important the rate of reproduction is to the survival of the species, that a cell well-adapted to one chemical environment may be poorly adapted to another chemical environment (and vice versa), that a colony of cells that specializes and works together can extend into environments where individuals cell may not survive, and how localizing metabolic pathways in organelles can significantly boost reaction rates if you are able to invest resources for infrastructure.

This game is intended to be used in the classroom. It integrates into the core middle school science curriculum and encourages students to climb Bloom’s taxonomy — to apply, analyze, evaluate, and synthesize — and enables them to explore concepts much more actively and through inquiry. Students are also given the opportunity to see and interact with the local mechanisms underlying cell processes, grounding their mental models on understandings that are both concrete and intuitive.