Membranes

In this section (IB Topic 1.3 )

- Discovery of the structure of biological membranes: Davson-Danielli vs Singer-Nicolson models

- Biochemistry of biological membranes: phospholipids, proteins and cholesterol

- Fluid mosaic model: on the move!

1.3_Vocabulary.pdf

Answers here.

Discovery of the structure of biological membranes

Electron microscopy of biological membranes

Under a transmission electron microscope, membranes appear like "trilaminar’ structures.

More than one model may be supported by a given piece of evidence.

Scientist knew that membranes were mainly composed of phospholipids and proteins, but the specific arrangement of these elements wasn't clear. The first model that attempted to describe the position of proteins within the bilayer was proposed by Hugh Davson and James Danielli in 1935. Their model was supported by systematic scientific observations through electron microscopes and biochemical data.

Drawing and labelling cell membranes: The Fluid Mosaic Model

Biochemistry of biological membranes

Phospholipid bilayer: hydrophobic and hydrophilic

See animation here.

Membrane proteins: integral vs peripheral

Fluid mosaic model

Click here to play with this animation of the biochemical structure of cell membranes.

Fluid mosaic model of cell membranesThe fluid mosaic model describes the cell membrane as a tapestry of several types of molecules (phospholipids, cholesterols, and proteins) that are constantly moving. This movement helps the cell membrane maintain its role as a barrier between the inside and outside of the cell environments.

Other stuff

Discovering the structure of biological membranes (very interesting article to read!)

resources part 1_cell membranes.pdf

resources part2_cellmembranes.pdf

Bubble lab

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