Chapter 7
Lipid bilayer as selective permeability field

The cell membrane defines the boundary that separates the internal environment of the cell from the external world.
Rather than being a static barrier, it is a dynamic interface that regulates exchange, communication, and stability.

This chapter explores the membrane as a coherence boundary that preserves cellular organisation while allowing controlled interaction with the surrounding environment.

Cells actively maintain differences in ion concentration across their membranes.
These gradients store energy that can be rapidly released to power transport, signalling, and metabolic processes.

This chapter explores ion gradients as reservoirs of potential tension, allowing biological systems to convert stored chemical imbalance into useful work.

Many molecules cannot pass directly through the lipid membrane and require specialised proteins to move across the cellular boundary.
These transport systems carefully regulate what enters and leaves the cell.

This chapter examines transport proteins as controlled boundary gates that manage molecular flow while preserving the stability of the cellular environment.