Which part of the living system did you change?
Labs / Biology
Mitosis
A single cell copies its DNA, lines the doubled chromosomes up along the middle, then pulls one identical copy to each end and pinches in two. Press play to watch the whole cycle, or scrub the timeline to freeze any phase. Flip on nondisjunction to see what happens when the split goes wrong.
Mitosis
A single cell copies its DNA, lines the doubled chromosomes up along the middle, then pulls one identical copy to each end and pinches in two. Press play to watch the whole cycle, or scrub the timeline to freeze any phase. Flip on nondisjunction to see what happens when the split goes wrong.
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
phase Interphaseper pole —DNA 2c
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- The DNA readout jumps from 2c to 4c early on, long before the cell divides. When did the copying actually happen, and why must it come first?
- Pause on metaphase and drag the metaphase plate sideways. Do the chromosomes still split into two equal groups no matter where the plate sits?
- Count the chromatids heading to each pole in anaphase. Why does every daughter end up with exactly the same set the parent started with?
- Turn on nondisjunction and step to telophase. Which daughter gets too many chromosomes, which gets too few, and what does "5 | 3" tell you?
- Slow the speed right down and watch the nuclear envelope. When does it disappear, and when do two new ones form?
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.