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Kinetics >
Stella
Tools
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#### This page poses questions to help
you think about the model presented below and the requirements for running the
model as a simulation using Stella.

## What's the model?

The following model is of the conversion
of glucose to glucose 6-phosphate. The enzyme that mediates this reaction is
hexokinase.

### What can we say about the model
based on how it is drawn?

Questions to answer:

- Is it an open or closed system?
- Reversible or irreversible?
- Which variables (stocks) influence
the rate of the reaction?
- Which rate law describes the reaction?

**Initial Concentrations**: For
the reaction to occur there must be some amount of material, molecules or stocks.

**Rate law**: Stella must be told
how to move stocks of glucose to glucose 6-phosphate. Since we are looking at
enzymatic reactions, the "how" is commonly stated in the form of an
enzymatic rate law. Enzymatic rate laws are also known as kinetic models.

**Rate constant**: *k* is
the common notation for a rate constant. A rate constant is most often used
in the rate law known as the law of mass action.

#### What do the results suggest? Beware
approximations

The results of a simulated model
are a function of the structure of the model, the initial parameter values and
the methods used to calculate the results. The linked page provides a series
of simulation results. The structure of the model used to produce each result
is the same.