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Below are some simple examples of models of biological processes: Glucose uptake, Glucose conversion and endoplasmic reticulum uptake of calcium.

Each example provides a conceptual map of the process and the corresponding Stella concept map.

Each arrow represents a mechanism of changing the concentration or state of the molecules (glucose, glucose6phosphate or calcium). The biological mechanisms are not the same but may be represented with the same kinetic model.

Uptake of glucose into the cell:

Glucose
Concept map	Stella map

Kinetics: Mass action or Mass flux

Enzyme: glucose transporter

Biology: Commonly identified as first step of glycolytic pathway.

 

Conversion of glucose to glucose-6-phosphate:

Reaction map	Stella map

Kinetics: Michaelis-Menten, mass action

Enzyme: Hexokinase

Biology: Second step of glycolytic pathway. Hexokinase phosphorylates glucose ( ATP is required in vivo but not taken into account in this model).

Discussion exercises

 

Transport of calcium from cytosol to endoplasmic reticulum:

Reaction map	Stella map

Kinetics: Hill type reaction

"Enzyme": SERCA (Sarco-endoplasmic reticulum ATP ase) pumps

Biology: Calcium uptake to the endoplasmic reticulum. Calcium storage in ER is an integral aspect of calcium dynamics.