Marsnut← Back to Home

Calvin Cycle Builder

Calvin Cycle Builder cover

Build the Calvin cycle in order: ① fixation, ② and ③ reduction, ④ regeneration. Drag each step card into its slot (or tap it, keys 1-4). Reduction and regeneration need ATP and NADPH, so tap the gold and blue orbs from the light reactions to refill your pools. Wrong order costs 3 seconds. (Simplified: 1 CO₂ per turn.)

Move the mouse over orbs to collect them (cursor moves extra fast), drag cards into the ring, or tap a card to fill the next slot.

90 seconds of active play. P: pause. H: guide. Timers, points, pools, token arrivals and expiry are game mechanics; drawings are not to scale.

For the curious at heart. A pocket-sized collection of science-inspired games.
Made for a quick break, a little discovery, and one more round.

DESKTOP / TABLET / MOBILE · Your browser is your playground.

How to Play Calvin Cycle Builder

Place the four cards in order: Rubisco fixation, ATP-dependent phosphorylation, NADPH-dependent reduction, and RuBP regeneration. Tap a card or press its position key (1–4), or drag it into the next ring slot. Collect gold ATP and blue NADPH orbs by touch or mouse; the resource buttons and A/N keys collect an available orb. Each simplified turn fixes 1 CO₂ and uses 3 ATP and 2 NADPH. After three turns, one net G3P is exported. The Calvin cycle operates in the chloroplast stroma. Five of six G3P molecules are recycled to regenerate three RuBP molecules; this rearrangement is represented by one card.

Wrong order costs three seconds. Pause and help freeze the experiment. The illustration simplifies molecules, enzyme steps and rates.

Read the biology · NCBI Bookshelf