Chapter 19
state transition network

Metabolism is the network of reactions that sustains life by transforming matter and energy within the cell.
Rather than isolated reactions, metabolic processes operate as coordinated pathways that move chemical states through structured transitions.

This chapter explores metabolism as a directed flow system, where biological reactions form organised networks that maintain cellular function and stability.

Glycolysis is one of the most fundamental metabolic pathways, converting glucose into smaller molecules while releasing usable energy.
This process occurs in nearly all living cells and forms the starting point for many other metabolic reactions.

This chapter examines glycolysis as a sequence of controlled chemical transitions that initiate the cellular extraction of energy from nutrients.

The Krebs cycle continues the energy extraction process by further oxidising metabolic intermediates derived from glycolysis.
Through a circular series of reactions, it generates molecules that carry high-energy electrons for later use.

This chapter explores the Krebs cycle as a repeating metabolic loop that supports sustained energy production within the cell.

The electron transport chain converts the stored energy of electrons into a proton gradient across the mitochondrial membrane.
This gradient ultimately drives the production of ATP, the primary energy currency of the cell.

This chapter examines the electron transport chain as a structured energy conversion system that links electron flow to cellular energy generation.

Cells continuously transform energy from one form into another to sustain biological processes. Chemical energy from nutrients is converted into gradients, molecular motion, and cellular work.

This chapter explores how biological systems maintain coherent energy transformations that support stable and sustained cellular activity.

Biological reactions must occur within strict physical and chemical constraints to maintain cellular viability.
Enzymes, compartmentalisation, and regulatory mechanisms ensure that metabolic flows remain controlled and efficient.

This chapter explores how metabolic systems preserve essential constraints while directing chemical flow through complex biological networks.