Growth begins in a cell.
What fraction of root cells is dividing? Prepare a slide, observe, and build an answer from your own count. A second preparation will put your hypothesis to the test.
In the eyepiece, drag the image to move the slide, use the wheel or the strip on the right to focus, and the nosepiece on the left to change objective. Click a name or an object to look closer, double-click the bench to step back. Slide the view with shift + scroll, the arrow keys, a right-button drag or two fingers.
Four precautions before touching anything: goggles, gloves, two corrosive acids to locate on the bench, and a scalpel blade to point the right way.
Protocol and completed steps
What the simulation idealises
- The 23-hour cycle and phase durations are teaching parameters, not universal onion constants.
- The hydrolysis bath and rinse are off-screen; times are accelerated. Model quality thresholds do not replace a validated laboratory protocol.
- Acetic orcein stains and contributes to fixation. The microscope shows fixed tissue; atlas animation is a reconstruction.
- Cycling cells have uniform ages by construction. Real asynchronous populations need not have that distribution.
- Four reference fields are simulated and preselected, never presented as student results.
- Sample B models a reduced cycling fraction. Other disturbances may affect the index differently.
- A preparation has depth: one focal plane does not sharpen every cell equally.
- The interphase–prophase transition can be ambiguous. The visibility cutoff is a model convention, not a universal ×400 limit.
- Differentiated root-cap cells do not cycle in this model. Root regions differ in activity.
- Fields yield different counts. Variability is not a reason to choose a preferred result.
The laboratory notebook
Saved on this device. Restart clears the notebook; export it to keep a copy. Bench progress is separate.
Your first count will appear here. No counts are supplied for you.