2.4 Membranes

Crash Course Biology: In Da Club – Membranes and Transport, by Hank

Essential Biology 2.4: Membranes

Fluid Mosaic Model Tutorial from Davidson.edu

For lots more animations on cell structure and function and cell transport, visit North Harris College.

You can also work through the Membranes lessons from HippoCampus Biology.

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Membrane Structure: The Fluid Mosaic Model

Fluid Mosaic Model Tutorial from Davidson.edu
Membranes organise cellular complexity and form spontaneously, from Learn.Genetics
Animated plasma membrane, by John Kyrk
Membrane structures and formation, from Carnegie Mellon

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Hydrophilic and hydrophobic properties maintain the phospholipid bilayer

Animated plasma membrane, by John Kyrk
Phospholipid bilayer, from YellowTang
Membrane structures and formation, from Carnegie Mellon

Membrane Fluidity

Membrane fluidity from Learn.Genetics
Animated plasma membrane, by John Kyrk
Membrane fluidity, from Carnegie Mellon
Membrane fluidity from John Gianni

The fluid nature of the plasma membrane allows for nuclear transfer to take place in cloning.

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Functions of Membrane Proteins

Hormone binding sites, immobilized enzymes, cell adhesion, cell-to-cell communication, channels for passive transport, and pumps for active transport.

Example of cell-cell communication from Learn.Genetics

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The plasma membrane is selectively permeable

Membrane permeability simulation, from Carnegie Mellon

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Diffusion and Osmosis

How diffusion works, from McGraw Hill
Diffusion applet from Ohio Biosci
Diffusion animation, by John Kyrk

How osmosis works, from McGraw Hill
Clear osmosis animation, from StOlaf.edu
Membrane transport, from Wiley Interactive Concepts in Biochemistry
Isotonic Equilibrium: Osmosis Simulation, from Carnegie Mellon

Try these in the lab: Plasmolysis of Elodea and of onion cells.

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Facilitated Diffusion

PhET Lab simulation: Membrane Channels (allow Java to run)
Membrane transport, from Wiley Interactive Concepts in Biochemistry
How facilitated diffusion works, from McGraw Hill
Facilitated diffusion, from Northland
Passive transport: simple and facilitated diffusion from Freeman Lifewire

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Active Transport & ATP

Membrane transport, from Wiley Interactive Concepts in Biochemistry
Sodium-potassium pump, from McGraw Hill
Sodium-potassium pump, from StOlaf
Active transport from Northland
Active transport from Freeman Lifewire

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Vesicle Transport: Endo- and Exocytosis

Vesicle transport from Learn.Genetics
Vesicle transport tutorial from Sumanas
Exocytosis, from StOlaf
Animated plasma membrane, by John Kyrk
Phagocytosis (endocytosis), from McGraw Hill
Endocytosis & exocytosis from McGraw Hill
Endoplasmic reticulum and Golgi apparatus, from Freeman Lifewire
Lysosomes, from McGraw Hill
Liposomes can be used to transport drugs, from Aberdeen University

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Amoebae are single-celled eukaryotes, which can carry out all the functions of life. The fluidity of their plasma membrane allows them to feed through phagocytosis (endocytosis of solids):