Which part of the living system did you change?
Labs / Biology
Cellular Respiration
Drag across the cell to drop in glucose, then set the feed rate and decide whether oxygen is available. Green sugars split in glycolysis, pyruvate feeds the Krebs cycle, and amber electron carriers (NADH & FADH₂) shuttle to the membrane where a proton gradient spins ATP synthase. Switch off oxygen and the whole engine falls back to fermentation.
Labs / Biology / Cellular Respiration
Cellular Respiration
Drag across the cell to drop in glucose, then set the feed rate and decide whether oxygen is available. Green sugars split in glycolysis, pyruvate feeds the Krebs cycle, and amber electron carriers (NADH & FADH₂) shuttle to the membrane where a proton gradient spins ATP synthase. Switch off oxygen and the whole engine falls back to fermentation.
Why it matters
Why explore this?
Living systems are connected and constantly changing. This model makes one biological process visible so you can test how its parts affect one another.
Explore
Try the model
ATP/glucose ≈ 38CO₂ 0O₂ used 0
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- With oxygen on, how many ATP does the cell squeeze out of one glucose? Where do almost all of them come from?
- Flip oxygen off. Why does the ATP-per-glucose readout crash from ~38 to just 2, and why do CO₂ and O₂ stop entirely?
- Watch the carriers. What actually makes ATP synthase spin faster — more glucose, or the proton gradient it builds?
- Crank the feed rate to maximum in fermentation. Can a sprinting muscle keep up with its energy demand this way, and for how long?
- If glycolysis alone still yields 2 ATP without oxygen, why did life bother evolving the whole Krebs-cycle-and-membrane machinery?
Explain
Make sense of what happened
Explain the process as a chain: a change happens, the system responds, and that response affects what happens next. Use an observation from the model as evidence.
Check
Before you leave
How did the system respond?
How would you explain that response?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.