Diffusion, Osmosis, and Movement Across a Membrane


Factors Affecting Diffusion Across a Plasma Membrane

Osmosis, the Passive Transport of Water

How Will Water Move Across Semi-Permeable Membrane?

Solution Types Relative to Cell

Osmosis Produces a Physical Force

Facilitated Diffusion

How to Cheat - Glucose Enters the Cell by Facilitated Diffusion

Regulation of Glucose Uptake by Insulin


Active Transport

The K+ / Na+ Pump: An Example of Active Transport

The The K+ / Na+ Pump

Other Active and Transport Mechanisms - The H+ / Sucrose Pump



Cellular Communication

Signal Transduction Pathways

Local Communication in Animal Cells

Hormonal Signaling in Plants and Animals

The Three Stages of Cell Signaling - Reception, Transduction, Response

G-Protein-Linked Receptor Sequences

Tyrosine-Kinase Receptors - Another Example of a Signal Transduction Pathway


Signal Transduction Pathways are often complex, having many, many intermediates participating in the cascade.