Enzymes and temperature sim
Set the water bath and watch iodine spots tell you when the starch is gone.
Enzymes: optimum temperature · covers the GCSE, O-Level topic
What the sim shows
A simplified model with typical values, not measured data. Amylase and starch sit in a water bath; every 30 s a drop of the mixture goes into iodine on the tile, blue-black while starch remains and orange-brown once it has been digested (time runs 40× faster here). Relative activity is an Arrhenius rise (Ea = 50 kJ/mol) times the fraction of enzyme still folded in a two-state unfolding (ΔHd = 300 kJ/mol, half unfolded at 41.4 °C, chosen to put the optimum at 37 °C), scaled to 100% at the optimum, about 37 °C as for human salivary amylase. Above the optimum the enzyme denatures: its active site changes shape and starch no longer fits. In reality denaturation is permanent. The starch is taken to vanish at 60 s ÷ activity, falling steadily until then. The last drop goes in at 7 min: if starch is still left then, the readout says "not gone after 7 min", or "no change" when activity is 1% or less. Real results also depend on pH, concentrations and how long the enzyme was heated.
- Thermometer needle: bath temperature
- Spotting tile: a drop of the mixture into iodine every 30 s
- Blue-black: starch left · orange-brown: starch gone
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