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4.2 Structure of membranes - Coggle Diagram
4.2 Structure of membranes
Fluid mosaic model
Fluid - phospholipids move around freely via diffusion
Mosaic - proteins scattered around + spread apart randomly
Phospholipid bilayer
Hydrophilic heads point outwards towards aqueous environment/ cytoplasm
Hydrophobic tails point inwards towards core of bilayer. Forms non-polar hydrophobic interior
More unsaturated phospholipids = tails more bent = looser fit = more fluid membrane
Longer tail = less fluid membrane
Lower temperature = less fluid (organisms add more unsaturated phospholipids to make membrane more fluid)
Proteins in membrane
Proteins have hydrophobic (non-polar) and hydrophilic (polar) regions
Hydrophobic regions point into hydrophobic core of membrane, repelled by water
Hydrophilic regions point outwards towards aqueous environment/cytoplasm, repelled by hydrophobic core
Protein spanning whole membrane - transmembrane protein
Some proteins fixed in place, most move freely
Phospholipids
Hydrophilic polar head, hydrophobic non-polar tail
When mixed with water, forms ball-like micelles or sheet-like bilayer
Bilayer = 7nm wide