Purpose: To become oriented with the model* and the software. This exercise was designed to work with Stella Demo or Player.

Click through the levels of the model (interface to model and equations) using the up and down arrows in the top left corner.

The values in the right hand column of the tables “Variable values” and “Vmax of other reactions” can be changed by typing directly into the cell.

Exploration

1. Run the simulation with the slider for “Vmax Cyclin degradation” to the far left (0.02).

What results do you see in the graphs?

How are the reaction velocities changed?

Does it matter if you change the initial values of the variables?

2. Re-run the simulation with the slider for “Vmax Cyclin degradation” placed to the far right (0.6)?

What results do you see?

How are the reaction velocities changed?

Does it matter if you change the initial values of the variables?

At what ~value of Vmax cyclin degradation are oscillations lost?

Note: Non-degradable cyclin is one of the experimental tools used to characterize cell cycle dynamics.

*Requests for the modified Goldbeter model can be made to Dr. Raquell Holmes at raquell@bu.edu.