The fluid-mosaic model: arrangement and movement of phospholipids, proteins, glycoproteins and glycolipids
The fluid-mosaic model describes the cell membrane as a flexible, constantly moving double layer of fat-based molecules. Proteins, glycoproteins, and glycolipids sit within or on this layer, each doing a different job.
Real World
Singer and Nicolson proposed the fluid-mosaic model in 1972 after freeze-fracture electron microscopy revealed proteins scattered irregularly — like tiles in a mosaic — across the membrane surface.
Exam Focus
Explain 'fluid' (phospholipids move laterally) and 'mosaic' (proteins vary in type and position) separately — examiners award a mark for each term.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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